Forensic Applications of Microscopy: Fibers 99

28/10/13 9:42 AM © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC & Bartlett Learning, © Jones SALE OR DISTRIBUTION NOT FOR LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE

© Darren Baker/ShutterStock, Inc. © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

9781449691790_CH04_FINAL.indd 82

NOT FOR SALE OR DISTRIBUTION NOT FOR © Jones & Bartlett Learning, LLC & Bartlett Learning, © Jones

NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC

NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning,

NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTIONCHAPTER The Microscope © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC and ForensicNOT FOR SALE OR DISTRIBUTION 4NOT FOR SALE OR DISTRIBUTION Identification© Jones & Bartlett Learning, LLC of © Jones & Bartlett Learning, LLC Hair,NOT FOR SALE Fibers, OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

In this chapter you should© Jones gain an & understanding Bartlett Learning, of: LLCOn the Crime Scene—Serial© Jones & Bartlett Learning, LLC ● The parts of a compoundNOT FOR microscope SALE and OR how DISTRIBUTION Murderer Everett BellNOT IdentifiedFOR SALE OR DISTRIBUTION it works by “Nubs” ● The use of a comparison microscope to compare two objects See You in Court ● ©The Jones large working & Bartlett distance Learning, and the larger LLC © Jones & Bartlett Learning, LLC Back At the Crime Lab NOTdepth FORof field SALE afforded OR by theDISTRIBUTION stereomicroscope NOT FOR SALE OR DISTRIBUTION ● Differentiation of amorphous and crystalline materials by use of a polarized light microscope ● The structure of hair and the microscopy tech- WRAP UP niques used to identify human hair © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ● The characteristics of natural fibers, human- Chapter Spotlight NOT FOR SALEmade OR fibers, DISTRIBUTION and the fabrics made with both NOT FOR SALE OR DISTRIBUTION types of fibers Key Terms ● The composition of different types of paints and how paint samples are characterized Putting It All Together

● The use of microspectrophotometers© Jones & Bartlett and scan- Learning, LLC © Jones & Bartlett Learning, LLC ning electron microscopesNOT FOR in the SALE forensic OR lab DISTRIBUTIONFurther Reading NOT FOR SALE OR DISTRIBUTION

9781449691790_CH04_FINAL.indd 83 28/10/13 9:42 AM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONYOU ARE THENOT FORENSIC FOR SALE ORSCIENTIST DISTRIBUTION

The microscopic techniques used to investigate trace fiber and hair evidence focus on their morphology. Morphology is a term that is used© Jones to describe & Bartlettthe size, shape, Learning, and color LLC of the evidence. The methods© employedJones &for Bartlett morphological Learning, LLC comparisons of questionedNOT FOR and controlSALE samples OR DISTRIBUTION often are used to show that two samplesNOT do not FOR match. SALE Indeed, OR more DISTRIBUTION suspects are exonerated by morphological comparison than are implicated by it. Only very rarely will the examiner be able to confirm that the individual who left behind the questioned trace sample was the same person who is the source of the control sample. © JonesThe utility & ofBartlett morphological Learning, comparison LLC methods is limited because© morphology Jones & often Bartlett is not capableLearning, of individual LLC - izingNOT hair FOR and fibers.SALE When OR twoDISTRIBUTION samples are similar enough to have originatedNOT FOR from SALEthe same OR person, DISTRIBUTION additional tests must be performed to establish their origin. 1. A bank was robbed by a man wearing a black ski mask. In a subsequent search of the bank parking lot, police recovered a black ski mask. What trace evidence might be present? How should that evidence be investigated? © Jones & Bartlett2. The examinersLearning, at the LLC forensic lab found a short,© brown Jones beard & hair Bartlett inside theLearning, ski mask. ShouldLLC the investigators NOT FOR SALEfocus OR theirDISTRIBUTION search on men with brown beards? NOT FOR SALE OR DISTRIBUTION

Introduction© Jones & Bartlett Learning, LLC Magnifying Small© Jones Details & Bartlett Learning, LLC During the searchNOT of aFOR crime SALE scene, OR investigators DISTRIBUTION Forensic scientists oftenNOT are FORconfronted SALE with OR the DISTRIBUTION will inevitably encounter many types of physical need to analyze many different types of materials evidence. Although the search may initially focus obtained during criminal investigations. The iden- on large objects that may prove to be evidence, tification or comparison of minuscule traces of a trace© Jones evidence & Bartlett must not Learning, be overlooked. LLC Trace evi- wide range© Jones of materials & Bartlett is a common Learning, occurrence LLC denceNOT FORis a generic SALE termOR DISTRIBUTIONused to describe small, in a modernNOT crimeFOR SALElab. The OR earliest DISTRIBUTION detectives— often microscopic, objects that are readily trans- including the fictional Sherlock Holmes—used ferred between people and places. The range of magnifying glasses to carefully examine evidence in objects falling into the category of trace evidence is the field and microscopes to study objects brought enormous and can include hair, fibers, glass, soil, to their laboratories. © Jones & Bartlettfeathers, Learning,pollen, dust, LLC and paint. © Jones &Early Bartlett crime Learning, labs relied almostLLC entirely on the NOT FOR SALEIn OR 1932, DISTRIBUTION with a borrowed microscope andNOT a FORlight SALEmicroscope OR DISTRIBUTIONfor examining minute details of few other pieces of basic equipment, the Federal evidence that were not visible to the naked eye. Bureau of Investigation (FBI) established its tech- This kind of a microscope offered less than 10 nical laboratory in Washington, DC. The micro- times (10×) magnification capabilities but was still scopic comparison© Jonesof fibers & and Bartlett hairs was Learning, among LLCconsidered a wonder. © Jones & Bartlett Learning, LLC the first examinationsNOT FORperformed SALE by OR this DISTRIBUTION labora- NOT FOR SALE OR DISTRIBUTION tory. Since then, forensic laboratories (including Refraction the FBI laboratory) have greatly expanded their capacity to handle trace evidence thanks to the A magnifying glass is a lens that is thicker in the development of modern analytical instruments. middle than at the edge. It makes objects appear Even© Jones with much& Bartlett more Learning,sophisticated LLC instruments larger than© Jones they are & Bartlettby refracting Learning, (bending) LLC light available,NOT FOR however, SALE forensicOR DISTRIBUTION scientists today usu- rays as NOTthey repeatedlyFOR SALE pass OR through DISTRIBUTION the air and ally begin their examination of trace evidence back through the lens. When light passes at an angle with a microscope. This chapter describes the through the interface between two transparent various types of microscopes available in forensic media (e.g., air and glass) that have different densi- © Jones & Bartlettlaboratories Learning, that are LLC used to examine hairs and© Jones ties, & an Bartlett abrupt changeLearning, in direction—that LLC is, refrac- NOT FOR SALEfibers. OR DISTRIBUTION NOT FORtion —ofSALE the ORbeam DISTRIBUTION is observed as a consequence of

84 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 84 28/10/13 9:42 AM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

FIGURE 4-1 The glass on the left shows the apparent position of a straw in water as seen by the eye. Refraction makes it appear that the straw is broken at the surface of the water. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

the difference in the velocity of the light in the two media. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The phenomenon of refraction is commonly NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION observed with an object that is immersed in a glass of water. For example, when a glass of water contains a straw ( FIGURE 4-1 ), refraction makes it appear that the straw is broken at the surface of the water.© Jones As the & raysBartlett of light Learning, leave the waterLLC and © Jones & Bartlett Learning,Retina LLC enterNOT the air, FOR their SALE velocity OR increases, DISTRIBUTION causing them NOT FOR SALE OR DISTRIBUTION to be refracted. How much light bends (and thus Simple the focal length) depends on the change in the Magnifying refractive index (η) as the light enters and leaves Lens the magnifying glass. The refractive index is a ratio © Jones &of Bartlettthe velocity Learning, of light in LLC a vacuum to its velocity © Jones & Bartlett Learning, LLC NOT FORin SALE any other OR medium: DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Velocity of light in a vacuum Refractive Index = η = ———––———–———————— Velocity of light in a denser medium © Jones & Bartlett Learning, LLC © Jones &Subject Bartlett Learning, LLC The refractive index is 1.0 for air and 1.33 for water NOT FOR SALE OR DISTRIBUTIONVirtual NOT FOR SALE OR DISTRIBUTION at 25°C. A typical glass has a refractive index of Image about 1.4 (a difference of 0.4 for light passing from air to glass). To use a magnifying glass to examine an object,© Jonesyou look & Bartlettthrough theLearning, lens ( FIGURE LLC 4-2 ). © Jones & Bartlett Learning, LLC The NOTmagnified FOR image SALE is ORcalled DISTRIBUTION the virtual image. NOT FOR SALE OR DISTRIBUTION As the lens is moved closer to the eye, the virtual image increases in size by 5 to 10 times. Higher magnification requires two lenses that are at fixed © Jones &distances Bartlett from Learning, each other LLC in a hollow tube, a setup © Jones FIGURE &4-2 Bartlett As light passes Learning, through a magnifyingLLC lens, the image of the bullet becomes magnified. NOT FORknown SALE as OR a compound DISTRIBUTION microscope. NOT FOR SALE OR DISTRIBUTION

Refraction 85

9781449691790_CH04_FINAL.indd 85 28/10/13 9:42 AM © Jones & BartlettTypes Learning, of Microscopes LLC © Jones & Bartlett Learning, LLC Ocular Lens NOT FOR SALE OR DISTRIBUTIONMirror NOT FOR SALEA microscope OR DISTRIBUTION has at least two lenses: an objective lens and an ocular lens or eyepiece ( FIGURE 4-3 ). The objective lens, which is the lower lens in the Head hollow tube, produces a “real” image—a magnified and inverted© version Jones of &the Bartlett object being Learning, exam- LLC © Jones & Bartlett Learning, LLC Arm Turret ined. The real imageNOT isFOR then SALE viewed OR through DISTRIBUTION the NOT FOR SALE OR DISTRIBUTION ocular lens (the smaller lens at the other end of the hollow tube in the eyepiece), producing a Objective Lens virtual image in the brain of the viewer. The vir- Stage tual© Jones image is& aBartlett magnified Learning, image produced LLC in the © Jones & Bartlett Learning,Condenser LLC viewer’s mind of the real image; it has the same Focus NOT FOR SALE OR DISTRIBUTION KnobNOT FOR SALE OR DISTRIBUTION orientation as the real image, but its magnification exceeds the magnification of the real image by the FIGURE 4-4 Base ocular lens ( ). The magnification power Illuminator of a microscope is greater than that of a magnifying © Jones & Bartlettglass because Learning, the former LLC device has two lenses. The© Jones FIGURE & Bartlett 4-3 A typical Learning, compound microscope LLC uses a light NOT FOR SALEmagnifying OR DISTRIBUTION power of a microscope is determinedNOT FORbulb SALEto illuminate OR the DISTRIBUTION specimen (light microscope). by multiplying the power of the objective lens by the power of the ocular lens. A compound microscope can magnify objects up to 1,500 times. depends on the wavelength of the light used to A compound© microscope—even Jones & Bartlett one Learning, with per- LLCilluminate the object. Wavelength© Jones & is Bartlettmeasured Learning, in LLC fect lenses using a tungsten light bulb to illuminate units of micrometers (µm; also known as microns), NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION the object—has limitations, however. In particular, where 1 µm is equal to 0.001 mm. The wavelength its ability to distinguish extremely small objects of white light (which is typically used to illuminate

© Jones & Bartlett Learning,FIGURE 4-4 The LLCpassage of light through two lenses© Jonesforms a virtual & Bartlett image of the Learning, object as seen LLC by the eye. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

86 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 86 28/10/13 9:42 AM objects in compound microscopes) is 0.55 µm, There are several types of electric lighting © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC and a compound microscope can distinguish (illuminators) for microscopes. Tungsten is the NOT FORobjects SALE that OR are DISTRIBUTION roughly one-half of that size (i.e., NOTleast FOR expensive SALE electricOR DISTRIBUTION illumination; it is also hot- 0.275 µm). Smaller objects—if they are seen at ter and less bright than the other kinds of illumi- all—may appear as a blur. To compensate for this nators. Fluorescent provides cooler and brighter shortcoming, some compound microscopes use light than tungsten. This is beneficial when you are blue light (which has© Jonesa shorter & wavelengthBartlett Learning, than viewingLLC slides for long periods© Jones of time or& whenBartlett you Learning, LLC white light) to illuminateNOT theFOR object SALE of interest. OR DISTRIBUTIONare observing live specimens,NOT such FOR as SALEprotozoa. OR DISTRIBUTION Five types of microscopes are typically used for Halogen provides the very brightest illumination. forensic examinations: In the condenser, the light rays from the illu- 1. Compound microscope minator are focused through a lens in the center of the stage and onto the specimen. The condenser 2. Comparison© Jones & microscope Bartlett Learning, LLC © Jones & Bartlett Learning, LLC has an iris diaphragm that can be opened or closed 3. StereoscopicNOT FOR microscopeSALE OR DISTRIBUTION to regulate NOTthe amount FOR SALEof light OR passing DISTRIBUTION into the 4. Polarizing microscope condenser. 5. Microspectrophotometer The eyepiece is the part of the microscope that Each of these microscopes has a specific function you look through. The objective is the second lens © Jones &that Bartlett makes itLearning, very effective LLC for obtaining certain © Jonesof the microscope.& Bartlett CompoundLearning, microscopes LLC have a NOT FORtypes SALE of information. OR DISTRIBUTION The scanning electron micro- NOT“nosepiece” FOR SALE with OR a rotating DISTRIBUTION objective turret, which scope (SEM), which can provide magnification of allows you to change the objective lens and ampli- more than 100,000 times, also is occasionally used fication power. The viewed image is magnified by for forensic examination of evidence. both the objective and the eyepiece lens. Thus the total magnification is equal to the product of the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Compound Microscopes magnifying power of the two lenses. For example, NOT FOR SALE OR DISTRIBUTIONif the eyepiece lens has a magnificationNOT FOR ofSALE 10× and OR DISTRIBUTION The mechanical system of a compound microscope the objective lens has a magnification of 40×, the has six important parts: total magnification will be the product of the two ● Base: The stand on which the microscope sits. lenses’ magnifications: 10 × 40 = 400×. Forensic ● Arm:© Jones A metal & pieceBartlett that supportsLearning, the LLCtube body examiners typically© Jones use & a Bartlett 10× eyepiece Learning, with nose LLC- ofNOT the microscope.FOR SALE It ORis also DISTRIBUTION used as a handle to piece that containsNOT FOR a 4×, SALE10×, 25×, OR or DISTRIBUTION 40× objective pick up the microscope. lens, providing magnification of 40×, 100×, 250×, or 400×, respectively. ● Body tube: A hollow tube that holds the objective lens at the lower end and the eyepiece lens Each objective lens is stamped with a numeri- cal aperture (NA). As the NA doubles, the lens is © Jones & Bartlettat the upper Learning, end. Light LLC passes from the objec- © Jones & Bartlett Learning, LLC tive lens through the body tube to the eyepiece, able to resolve details that are half as distant from NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION where it is observed by the eye. each other (twice as close to each other). The NA is effectively an index of the ability of the objec- ● Stage: The platform that supports the speci- tive lens to resolve fine detail. The higher the NA men. The specimen is placed on a glass slide (up to about 1000× the NA), the more detail the that is clipped into place on the stage. The microscope can discern. Anything beyond 1000×, x- and y-axis stage© Jonescontrol &knobs Bartlett are used Learning, to LLC © Jones & Bartlett Learning, LLC however, is considered “empty magnification” that move the slide backNOT and FOR forth SALE under theOR objec DISTRIBUTION- NOT FOR SALE OR DISTRIBUTION doesn’t add anything to the clarity of the image. tive lens. The forensic examiner must balance the micro- ● Coarse adjustment: A knob that focuses the scope’s magnifying power with both the field of microscope on the specimen by raising and view and the depth of focus. The field of view is lowering© Jones the & body Bartlett tube ofLearning, the microscope. LLC the area that© the Jones forensic & examinerBartlett seesLearning, when look LLC- ● FineNOT adjustment: FOR SALE A knob OR thatDISTRIBUTION adjusts the height ing throughNOT the eyepiece. FOR SALE As the OR magnifying DISTRIBUTION power of the body tube in smaller increments so the increases, the field of view shrinks. The examiner specimen can be brought into fine focus. should start with a low magnification. After tak- The optical system has four fundamental parts: ing in this (relatively) “big picture,” the examiner © Jones &the Bartlett illuminator, Learning, the condenser, LLC the eyepiece, and © Jonesshould &switch Bartlett to a Learning,higher-power LLC objective lens to NOT FORthe SALE objective. OR DISTRIBUTION NOTscrutinize FOR SALE particular OR DISTRIBUTIONparts of the specimen more

Types of Microscopes 87

9781449691790_CH04_FINAL.indd 87 28/10/13 9:42 AM on the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONCRIME NOT FOR SALE OR DISTRIBUTION SCENE Serial Murderer Everett Bell Identified by “Nubs”

On August 22, 1995,© Jones the body & ofBartlett 8-year-old Learning, Sandra was LLCdiscovered by police in a wooded© Jones area near & her Bartlett church in Learning, LLC southern Michigan.NOT The FOR child SALEhad been OR brutally DISTRIBUTION assaulted before she died of strangulation.NOT Her FOR bicycle SALE was found OR DISTRIBUTION near her partially hidden body. Police cordoned off the wooded area and the adjacent church parking lot to per- form a detailed search of the area. Fingerprints were taken from the victim’s body and from the bicycle. The coroner discovered material under Sandra’s fingernails, on her abdomen, and on her hands. Vaginal and ©rectal Jones swabs & andBartlett analysis Learning, of her clothing LLC revealed no biological material© Jones other &than Bartlett her own. Learning, Furthermore, LLC the NOTbicycle FOR provided SALE no incriminatingOR DISTRIBUTION fingerprint evidence. However, hairNOT and fibers FOR were SALE found OR on theDISTRIBUTION victim. The police launched a major investigation, canvassing the neighborhood around the church. They found that Everett Bell, a local resident and an employee of a Hardee’s® restaurant, was seen in the area around nightfall riding his bicycle. Bell’s employer revealed that Bell had been sent home early from work that day. The Hardee’s manager gave police Bell’s work pants, shirt, and cap. © Jones & BartlettThe Learning, FBI laboratories LLC found blue cotton fibers ©under Jones Sandra’s & Bartlettfingernails. Learning, When they were LLC examined under a NOT FOR SALEmicroscope, OR DISTRIBUTION it was clear that these fibers matched NOTthe blue FOR cotton SALE fibers fromOR theDISTRIBUTION suspect’s shirt. Blue and green fibers found on Sandra’s clothes also matched those from the shirt. In addition, a dark blue-gray polyester fiber matching the fibers of the suspect’s pants matched fibers found on the rectal swab. Of particular interest, the sample from the victim contained “nubs”; the end of the fiber was melted during manufacture into bulbs that are called nubs. The© nubs Jones that were& Bartlett lifted with Learning, tape from Bell’s LLC shirt matched the nubs lifted© Jones from the & surface Bartlett of the Learning, LLC victim’s shirt. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Hardee’s employees were given particular shirts manufactured by WestPoint Stevens Alamac Knits. Bell’s shirt was a short-sleeve polo shirt that Hardee’s had recently replaced with a striped shirt. Therefore, few of the solid shirts were still being worn by employees. Tape applied to the surface of Bell’s shirt removed a significant number of the nubs that proved to be identical to nubs found on the victim’s clothes, establishing physical contact © betweenJones the & Bartlettvictim and Learning,the suspect. LLC © Jones & Bartlett Learning, LLC NOT BellFOR later SALE confessed OR to DISTRIBUTION Sandra’s murder as well as to five other rapesNOT and FOR at least SALE nine ORother DISTRIBUTION murders.

closely. The examiner should also adjust the depth is essentially two compound microscopes that are © Jones & Bartlettof focus Learning, (the thickness LLC of the region in focus,© Jonesconnected & Bartlett by an Learning, optical bridge—that LLC is, a series of NOT FOR SALEwhich OR affects DISTRIBUTION the clarity of the image) as necesNOT- FORmirrors SALE and ORlenses DISTRIBUTION that link the two microscopes’ sary. As with the field of view, when the magnify- objective lenses. The comparison microscope has a ing power increases, the depth of focus decreases. single eyepiece through which the forensic exam- Thus both field of view and depth of focus iner sees the images from both compound micro- decrease as magnifying© Jones power & Bartlettincreases. Learning, As a con- LLCscopes placed side by side.© Jones & Bartlett Learning, LLC sequence, high powersNOT FOR of magnification SALE OR DISTRIBUTIONsacrifice Comparison microscopesNOT FORthat compareSALE OR semi DISTRIBUTION- both the size of the area in view and the thickness transparent hairs and fibers are lighted from below of the region in focus. Low powers of magnifica- the stage. Other comparison microscopes are tion sacrifice detail within the region under exami- designed to compare bullets, bullet cartridges, and nation and in focus. For this reason, a trade-off is other opaque objects ( FIGURE 4-5 ). Because these necessary© Jones when & Bartlett using a Learning,compound microscope. LLC specimens© Jones do not transmit& Bartlett light, Learning, illumination LLC from NOT FOR SALE OR DISTRIBUTION below theNOT stage FOR is SALEnot possible; OR DISTRIBUTION instead, optical Comparison Microscopes microscopes for viewing these items are equipped To compare two specimens, such as evidence taken with a vertical or reflected illumination system from a crime scene with a reference sample taken ( FIGURE 4-6 ). © Jones & Bartlettfrom a suspect, Learning, the forensic LLC examiner often uses© a Jones &An Bartlett experienced Learning, examiner LLC will mount the evi- NOT FOR SALEcomparison OR DISTRIBUTION microscope. A comparison microscopeNOT FORdence SALE on the OR same DISTRIBUTION side for all comparisons. For

88 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 88 28/10/13 9:42 AM Courtesy of Leica Microsystems, Inc. Microsystems, Leica of Courtesy Inc. Microsystems, Leica of Courtesy © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION FIGURE 4-5 This comparison microscope is used to compare the marks or scratches on a bullet recovered from a crime scene to a test bullet fired from a gun suspected of being a murder weapon. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Ocular Lens

Objective Lens © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC FIGURE 4-7 Although it will magnify only 125x, the ste- Light Source NOT FOR SALE OR DISTRIBUTIONreomicroscope is the most commonlyNOT used FOR microscope SALE in OR DISTRIBUTION Light Source forensics.

© Jones & Bartlett Learning, LLC The stereoscopic© Jones microscope& Bartlett hasLearning, several fea LLC- Working NOT FOR SALE OR DISTRIBUTION tures that makeNOT itFOR particularly SALE OReasy DISTRIBUTION to use. This Distance device has two eyepieces, which make it more comfortable for the viewer. It also produces a three-dimensional image that is presented in a Stage right-side-up, frontward orientation (unlike the © Jones & Bartlett Learning, LLC © Jonesupside-down, & Bartlett backward Learning, orientation LLC of the image NOT FOR SALE OR DISTRIBUTION NOTproduced FOR SALE by a compoundOR DISTRIBUTION microscope). Its large FIGURE 4-6 This microscope is lit from above and is used to working distance, which is the distance between examine opaque materials. the objective lens and the specimen, means that the forensic examiner can use this device to view large items. Finally, the stereoscopic microscope © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC instance, an examiner who is right handed should can be lighted either from below, to illuminate always place the evidenceNOT onFOR the SALEright microscope OR DISTRIBUTION semitransparent objects, or NOTvertically FOR from SALE above, OR DISTRIBUTION stage and the reference material on the left stage. to illuminate opaque objects. When this is done without fail, the evidence and the standard reference will not be confused. Polarizing Microscopes © Jones & Bartlett Learning, LLC The compound© Jones microscope & Bartlett has been Learning, used to deter LLC- StereoscopicNOT FOR MicroscopesSALE OR DISTRIBUTION mine the typesNOT of FOR minerals SALE present OR DISTRIBUTION in geological The stereoscopic microscope ( FIGURE 4-7 ) is the samples for more than 100 years. Minerals whose most commonly used microscope in crime labo- atoms are arranged in random order are classified ratories. Although it is able to magnify images by as amorphous materials. Minerals whose atoms © Jones &only Bartlett 10× to 125×Learning, , many typesLLC of physical evidence © Jonesare arranged & Bartlett in a distinctLearning, order LLC are classified as NOT FORare SALE routinely OR examinedDISTRIBUTION under low magnification. NOTcrystalline FOR SALE materials. OR DISTRIBUTION

Types of Microscopes 89

9781449691790_CH04_FINAL.indd 89 28/10/13 9:42 AM By observing how light interacts with thin sec- © Jones & Bartlett Learning, LLC © Jones & Bartletttions of the Learning, minerals, theLLC forensic examiner can clas- NOT FOR SALEsify minerals—and OR DISTRIBUTION classification is the first step NOTin FORA. SALE OR DISTRIBUTION forensic identification. The classification techniques described here rely on the fact that light travel- ing through the minerals in different directions will behave differently,© Jonesbut predictably. & Bartlett These Learning, differ- LLC © Jones & Bartlett Learning, LLC ences can be detectedNOT with FOR a polarizingSALE OR microscope. DISTRIBUTION NOT FOR SALE OR DISTRIBUTION To examine and classify a mineral, the sample must B. be dry and thin enough to be placed on a microscope slide under a cover slip. If the material is too thick, a portion can be shaved off with a scalpel. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Isotropic materials—such as gases, liquids, andNOT cubic FOR crystals—have SALE OR DISTRIBUTIONthe same optical proper- FIGURE 4-8NOT (A) LightFOR from SALE a light ORbulb isDISTRIBUTION polarized in one ties when observed from any direction. Because plane as it passes through the first polarizer, and it will isotropic materials have only one refractive index, reach the eye only if the second polarizer is in the same position. (B) When the second polarizer is rotated, it cuts they appear the same when light passes through off the light and stops its transmission. © Jones & Bartlettthem from Learning, different directions.LLC By contrast, aniso-© Jones & Bartlett Learning, LLC NOT FOR SALEtropic OR (or DISTRIBUTIONbirefringent) materials—such as quartz,NOT FOR SALE OR DISTRIBUTION is rotated, less plane-polarized light is transmitted calcite, and asbestos—are crystalline. In anisotro- through the second lens, and, at a rotation of 90°, no pic minerals, the arrangement of atoms is not the light is transmitted ( FIGURE 4-8B ). same in all directions. Thus, when an anisotropic material is examined, the arrangement of atoms in © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC the substance appears to change as the direction Polarized Light Microscopy of observation changes.NOT FOR Photons SALE of ORlight DISTRIBUTION passing A polarizing microscopeNOT includes FOR twoSALE polarizing OR DISTRIBUTION through asbestos fibers from different directions filters: the polarizer lens, which is fixed in place will encounter different electrical neighborhoods, below the specimen, and the analyzer lens, which is which in turn will affect the path and time of travel located above the specimen ( FIGURE 4-9 ). The sample of© theJones light &beam Bartlett in different Learning, ways. LLC © Jones & Bartlett Learning, LLC

NOTBesides FOR providing SALE OR information DISTRIBUTION on the shape, NOT FOR SALE OR DISTRIBUTIONInc. Microsystems, Leica of Courtesy color, and size of different minerals, polarized light microscopy can distinguish between isotropic and anisotropic materials. This technique is used to identify the presence of certain minerals and their © Jones & Bartlettanisotropic Learning, properties. LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Plane-Polarized Light According to the wave theory of light, light waves oscillate (vibrate)© at Jones right angles & Bartlett to the direction Learning, in LLC © Jones & Bartlett Learning, LLC which the light is NOTtraveling FOR through SALE space. OR TheDISTRIBUTION oscil- NOT FOR SALE OR DISTRIBUTION lations occur in all planes that are perpendicular to the path traveled by the light. These oscillations may be produced by a light bulb and viewed by an observer looking directly into the beam ( FIGURE 4-8A ). If© theJones beam & of Bartlett light is Learning,passed through LLC a sheet of © Jones & Bartlett Learning, LLC PolaroidNOT FOR® material, SALE ORthe lightDISTRIBUTION that is transmitted NOT FOR SALE OR DISTRIBUTION through the Polaroid sheet oscillates in one plane only. Such light is called plane-polarized light. If a second Polaroid lens is inserted before your eye, that © Jones & Bartlettlens must Learning, be aligned in LLC a parallel plane so that plane-© Jones FIGURE & Bartlett 4-9 A polarizing Learning, microscope LLC includes two polarizing filters: the polarizer lens and the analyzer lens. NOT FOR SALEpolarized OR lightDISTRIBUTION is passed. If the second Polaroid lensNOT FOR SALE OR DISTRIBUTION

90 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 90 28/10/13 9:42 AM stage, which is placed between the two filters, can completed, the analyst can then hone in on small © Jones & Bartlett Learning, LLC © Jones be& Bartletteasily rotated. Learning, LLC details at higher magnification. When an interest- NOT FOR SALEBesides OR information DISTRIBUTION about the gross fiber mor- NOTing FOR characteristic SALE OR is identified, DISTRIBUTION its morphology can phology and color of the sample, analysis of plane- be compared with that of a reference material and polarized light can determine whether the sample its optical properties identified via a polarizing exhibits pleochroism. Pleochroism is the property microscope. that causes a substance© Jones to show & differentBartlett absorp Learning,- LLCIn the past 2 decades, ©microscopes Jones & Bartletthave also Learning, LLC tion colors when it NOTis exposed FOR toSALE polarized OR DISTRIBUTIONlight been attached to spectrophotometers.NOT FOR In SALE a spectro OR- DISTRIBUTION coming from different directions. The observed photometer, a lamp emits radiation—either ultra- colors change with the orientation of the crystal violet (UV) or infrared (IR)—that passes through a and can be seen only with plane-polarized light. sample. The sample absorbs some of this light, and As the sample stage is rotated, these substances the rest passes to the spectrophotometer. There, © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC change color. the light from the sample is separated according PolarizedNOT FOR light SALE microscopy OR DISTRIBUTION also is used to iden- to its wavelengthNOT (theFOR visible SALE range OR light DISTRIBUTION looks like tify human-made fibers and paint. If a fiber is col- a rainbow), and the spectrum formed is observed lected from a victim and placed on a microscope with a detector. Such analysis (spectroscopy) is slide, it may be difficult to tell one type of fiber used to elucidate the composition of unknown © Jones &from Bartlett another. Learning, If it is a LLCglass fiber, however, its © Jonesmaterials & Bartlettin many Learning,different fields. LLC Spectroscopy NOT FORcolor SALE will OR not DISTRIBUTION change as the microscope stage is NOTcan FOR also SALEbe used OR to DISTRIBUTIONmatch compounds, measure rotated. That is, because glass fibers are isotropic, concentrations, and determine physical structures. they are unaffected by rotation under polarized A microspectrophotometer combines the light. Other human-made fibers are anisotropic capabilities of a spectrophotometer with those of a and change colors as the stage is rotated. It is microscope. The microscope magnifies the image © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC an easy matter to compare the pleochroism of a of the specimen for the spectrometer and allows the fiber found at a crimeNOT scene FOR to a SALE fiber taken OR DISTRIBUTIONfrom forensic examiner to analyzeNOT extremely FOR smallSALE sam OR- DISTRIBUTION the suspect, thereby proving (or disproving) a link ples or a small region of a sample. The spectropho- between the suspect and the scene. tometer then measures the intensity of light at each wavelength. Microspectrophotometers (also called © Jones & Bartlett Learning, LLC microspectrometers,© Jones microscope & Bartlett spectrophotomLearning, LLC- MicrospectrophotometersNOT FOR SALE OR DISTRIBUTION eters, and microphotometers)NOT FOR SALE areOR extremely DISTRIBUTION use- The microscope allows the analyst to look over the ful. In addition to measuring the light absorbed general features of the object being investigated at or transmitted by the sample, a microspectropho- low power. Once a general survey of the object is tometer can measure the intensity of light reflected © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONSEE YOU IN COURT NOT FOR SALE OR DISTRIBUTION

In the late 1970s, a wave of child murders occurred Probabilities are difficult to establish in many, if in Atlanta. Wayne Williams© Jones was & arrested Bartlett for Learning,the ofnot LLC most, physical evidence cases.© Jones Determining & Bartlett the Learning, LLC fenses, based principallyNOT on FOR the carpet SALE fiber OR evidence DISTRIBUTION likelihood of a match for new NOTcar carpet, FOR for SALE exam- OR DISTRIBUTION found on the bodies, which was similar to carpet ple, would be possible if one knew how many cars fibers found in his vehicle. Williams was convicted with that type and color of carpet were sold within and sentenced to life in prison, where he remains a certain distance of the location of interest. Obvi- today. ously, as the area included increases, the probabilities © However,Jones &controversy Bartlett has Learning, dogged this LLC case since drop. Given that© Jones cars generally & Bartlett do not stay Learning, in confined LLC theNOT moment FOR the SALEfibers were OR introduced DISTRIBUTION into evidence. spaces, one wouldNOT haveFOR to SALEmake explicit OR DISTRIBUTIONassumptions Contrary to the practice today, the jury was never to justify the development of a probability statement. told that the fibers were not unique but rather heard No such evidence was employed in the Williams case, that they matched carpet fibers that could be found which is why this conviction remains tainted in the © Jones & Bartlettthroughout Learning, the Atlanta metropolitan LLC area. © Joneseyes of many& Bartlett modern forensicLearning, scientists. LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Types of Microscopes 91

9781449691790_CH04_FINAL.indd 91 28/10/13 9:42 AM from a sample, the intensity of light emitted when electron source found in the SEM, travel through a © Jones & Bartlett Learning, LLC © Jones & Bartletta sample Learning, fluoresces, LLCor the intensity of polarized specimen in a way that is similar to a beam of light NOT FOR SALElight afterOR DISTRIBUTIONit has interacted with a sample. NOT FORpassing SALE through OR aDISTRIBUTION sample in an optical microscope. Microspectrophotometers have numerous ad- Instead of glass lenses directing light wavelengths vantages over conventional spectrometers. For through a specimen, however, the electron micro- instance, they can easily take spectra of samples scope’s electromagnetic lenses direct electrons as small as 2.5 µm© Joneswide while & Bartlett viewing theLearning, sample LLCthrough a specimen ( ©FIGURE Jones 4-10B & ). Bartlett Because Learning,the LLC directly. The latterNOT feature FOR allowsSALE forOR more DISTRIBUTION pre- wavelength of electronsNOT is much FOR smaller SALE than OR the DISTRIBUTION cise measurements of the sample while eliminating wavelength of light, the resolution achieved by the interference from the surrounding material. Also, SEM is many times greater than the resolution because many human-made substances—even col- possible with the light microscope. Thus the SEM orless ones—absorb more in the UV region than in can reveal the finest details of structure and the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC the visible light and IR regions, microspectropho- complex surface of synthetic fibers ( FIGURE 4-11 ). tometersNOT FOR are SALEvery useful OR DISTRIBUTIONfor analysis of synthetic SomeNOT of the FOR electrons SALE striking OR DISTRIBUTION the surface of the fibers (discussed later in this chapter). sample are immediately reflected back toward the To see how this works, suppose that compari- electron source; these are called backscattered elec- son of two fibers—one found at a crime scene and trons. An electron detector can be placed above the © Jones & Bartlettthe other Learning, taken from LLCa suspect—using a polarized© Jones sample & Bartlett to scan Learning,the surface andLLC produce an image NOT FOR SALElight microscopeOR DISTRIBUTION indicates that the appearance andNOT FORfrom SALE the backscattered OR DISTRIBUTION electrons. Other electrons morphology of the two fibers are identical. When that strike the surface of the sample penetrate it; the fibers are analyzed in an IR microspectropho- they can be measured by an electron detector that tometer, each produces an IR spectrum. At first is placed beneath the sample. In addition, some of glance, the two spectra appear very similar and the electrons striking the surface cause X-rays to © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC indicate that both fibers are nylon. With a careful be emitted. By measuring the energy of the emit- comparison of theNOT two FORspectra, SALE however, OR smallDISTRIBUTION dif- ted X-ray, the elementalNOT composition FOR SALE of the OR sur DISTRIBUTION- ferences become apparent. When these IR spectra face can be determined through a technique called are compared with the IR spectra of known refer- energy dispersive X-ray spectroscopy (EDX). If a ence fibers, one fiber is found to be nylon-6 and fiber is coated with a dulling agent, such as tita- the© Jonesother nylon-6,6. & Bartlett Although Learning, the wordLLC nylon is nium dioxide,© Jones the EDX& Bartlett will detect Learning, its presence. LLC usedNOT to FOR describe SALE an entireOR DISTRIBUTION class of fibers, there are NOT FOR SALE OR DISTRIBUTION actually five common nylons sold commercially in the United States: nylon-6,6; nylon-6,12; nylon- Forensic Applications of 4,6; nylon-6; and nylon-12. All nylons share some Microscopy: Hair physical properties (such as solubility in solvent), © Jones & Bartlettbut some Learning, subgroups LLC differ in appearance and© JonesHair & isBartlett frequently Learning, the subject LLC of forensic examina- NOT FOR SALEabsorption OR DISTRIBUTION of dye due to differences in molecularNOT FORtion. SALE This analysis OR DISTRIBUTION has some limitations, however— structure. As this example shows, the microspec- namely, forensic examination of an individual hair trophotometer has the ability to differentiate fibers will not result in definitive identification of the per- that fall into the same generic class (nylon) but are son from whom the hair was shed, unless the hair structurally different© Jones (nylon-6 & Bartlettversus nylon-6,6). Learning, LLChas a tag attached that ©can Jones be analyzed & Bartlett for DNA. Learning, LLC NOT FOR SALE OR DISTRIBUTIONAt best, a hair’s morphologyNOT (when FOR comparedSALE OR with DISTRIBUTION Scanning Electron Microscopes a reference hair) may be consistent with the ref- When the evidence available is very small and erence hair; it cannot be said definitively to be a more magnification is needed, an SEM is often perfect match. Hair does not possess a sufficient used as part of the forensic analysis ( FIGURE 4-10A ). number of unique, individual characteristics to be An© JonesSEM can & magnify Bartlett an Learning, image 100,000 LLC times and positively© Jonesassociated & Bartlettwith a particular Learning, person LLC to hasNOT a depthFOR ofSALE focus OR that DISTRIBUTION is more than 300 times the exclusionNOT FORof all SALEothers. AlthoughOR DISTRIBUTION hair samples that available with an optical microscope. are commonly used to exclude a suspect, they can An SEM operates on the same basic princi- be considered only as contributing evidence—to ple as the polarizing microscope but uses elec- connect the suspect to the crime scene, for exam- © Jones & Bartletttrons rather Learning, than light LLC to identify properties ©of Jonesple, & or Bartlett to connect Learning, multiple LLC crime scene areas to NOT FOR SALEthe object. OR DISTRIBUTION Electrons, which are produced in theNOT FOReach SALEother through OR DISTRIBUTION transfer of evidence.

92 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 92 28/10/13 9:42 AM Courtesy of FEI Company. FEI of Courtesy © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

FIGURENOT 4-10 FOR (A) A scanningSALE electronOR DISTRIBUTION microscope (SEM). (B) A schematic diagram ofNOT an SEM. FOR SALE OR DISTRIBUTION

Forensic Applications of Microscopy: Hair 93

9781449691790_CH04_FINAL.indd 93 28/10/13 9:42 AM Arizona State University. State Arizona at Nature of Images Fessler, Shara of Courtesy © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning,Medulla LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Cortex

Pigment © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Cuticle Arizona State University. State Arizona at Nature of Images Fessler, Shara of Courtesy Cortical Fusi © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION FIGURE 4-12NOT The FOR shaft ofSALE a hair, showingOR DISTRIBUTION the cuticle, cortex, medulla, pigment, and cortical fusi.

© Jones & Bartlett Learning, LLC © JonesCuticle & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FORThe cuticleSALE consists OR DISTRIBUTION of scales of hardened, flattened, keratinized tissue that overlie the cortex. These scales have a shape and pattern that are unique Arizona State University. State Arizona at Nature of Images Fessler, Shara of Courtesy to the animal species from which they came—for © Jones & Bartlett Learning, LLCexample, the cuticle of ©a catJones hair &differs Bartlett from Learning,the LLC NOT FOR SALE OR DISTRIBUTIONcuticle of a human hairNOT ( FIGURE FOR 4-13 SALE). In addition, OR DISTRIBUTION the acidity of modern shampoos can be adjusted to make these scales stand up or lie down. When the scales lie flat, hair reflects light and has an attractive luster—think of the attractive model’s hair in a © Jones & Bartlett Learning, LLC shampoo© commercial.Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION OneNOT way FORto observe SALE the OR scale DISTRIBUTION pattern is to make a cast of the surface. To do so, the foren- FIGURE 4-11 (A) Cotton fibers, (B) rayon fibers, and sic examiner presses the hair into a soft material, (C) polyester fibers, as seen through a scanning electron such as clear nail polish or soft vinyl. Later, when microscope. © Jones & Bartlett Learning, LLC © Jonesthe & material Bartlett hardens Learning, and LLCthe hair is removed, the impression of the cuticle is left behind in the NOT FOR SALE OR DISTRIBUTION NOT FORclear SALE plastic. OR This DISTRIBUTION plastic will transmit light, so Hair Morphology the impression of the cuticle can be examined on the plastic’s surface with a compound microscope Hair is composed primarily of keratin, a very under high magnification. strong protein that© Jonesis resistant & Bartlettto chemical Learning, decom- LLC © Jones & Bartlett Learning, LLC position and canNOT retain FOR its structural SALE ORfeatures DISTRIBUTION for a NOT FOR SALE OR DISTRIBUTION long time. In fact, even hairs of ancient Egyptian Cortex mummies have been found to retain most of their The cortex consists of an orderly array of spindle- structural features. This durability makes hair shaped cortical cells, which is aligned parallel to resistant to physical change and an excellent class the length of the hair. The cortex contains pigment of© physicalJones evidence.& Bartlett Learning, LLC bodies, ©which Jones contain & Bartlett the natural Learning, dye melanin, LLC and NOTEach FOR strand SALE of hairOR DISTRIBUTIONgrows out of a tubelike cortical NOTfusi, whichFOR areSALE irregular-shaped OR DISTRIBUTION air spaces structure known as the hair follicle, which is of varying sizes. Cortical fusi are commonly found located within the skin. The shaft of each hair con- near the root of a mature human hair, although sists of three layers: the cuticle (the outer layer), they may be present throughout the length of the © Jones & Bartlettthe cortex Learning, (the middle LLC layer), and the medulla (the© Joneshair. & AsBartlett part of Learning, a side-by-side LLC comparison of evi- NOT FOR SALEinnermost OR DISTRIBUTION layer) ( FIGURE 4-12 ). NOT FORdentiary SALE hair OR samples DISTRIBUTION and reference hair samples,

94 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 94 28/10/13 9:42 AM © Dennis Kunkel Microscopy, Inc./Visuals Unlimited/Corbis Inc./Visuals Microscopy, Kunkel Dennis © medium that has about the same index of refrac- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC tion as the hair. This choice minimizes the amount NOT FOR SALE OR DISTRIBUTION NOTof FORreflected SALE light ORand DISTRIBUTIONoptimizes the amount of light that penetrates the hair, facilitating the observation of the cortex.

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONMedulla NOT FOR SALE OR DISTRIBUTION The medulla consists of one or more rows of dark- colored cells that run lengthwise through the center of the hair shaft. The shape of the medulla may be cylindrical (human) or patterned (animals). © Jones & Bartlett Learning, LLC The pattern© observed Jones is& specificBartlett to Learning, the particular LLC © M. Kaleb/Custom Medical Stock Photo Stock Medical Kaleb/Custom M. © NOT FOR SALE OR DISTRIBUTION species fromNOT which FOR the hairSALE came. OR DISTRIBUTION The medulla may be a continuous, fragmented, or interrupted line of dark cells. The medullar ratio (the ratio of the medullar diameter to the hair © Jones & Bartlett Learning, LLC © Jonesdiameter) & Bartlett for animal Learning, hair is generally LLC greater than NOT FOR SALE OR DISTRIBUTION NOT0.5; FOR the medullarSALE OR ratio DISTRIBUTION for human head hair is generally less than 0.33.

Hair Growth © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The root of the hair (refer to Figure 4-12) is sur- NOT FOR SALE OR DISTRIBUTIONrounded by cells that provideNOT all FOR the SALEnecessary OR DISTRIBUTION

© M. Kaleb/Custom Medical Stock Photo Stock Medical Kaleb/Custom M. © ingredients to generate hair and to sustain its growth. Human hair goes through three devel- opmental stages: the anagenic phase, catagenic © Jones & Bartlett Learning, LLC phase, and telogenic© Jones phase & Bartlett. The size Learning, and shape LLC of NOT FOR SALE OR DISTRIBUTION the hair rootNOT are differentFOR SALE in each OR of DISTRIBUTION these phases ( FIGURE 4-14 ). The anagenic phase is the initial growth phase, during which the hair follicle is actively producing the hair. During this phase, which may last as long © Jones & Bartlett Learning, LLC © Jonesas 6 years, & Bartlett the follicle Learning, is attached LLC to the root by the NOT FOR SALE OR DISTRIBUTION NOTdermal FOR papilla. SALE During OR DISTRIBUTION the anagenic phase, the hair must be “pulled” to be lost, in which case it may have a follicular tag. The follicular tag includes cells from the root that contain DNA ( FIGURE 4-15 ). FIGURE 4-13 The cuticle patterns of hairs differ among species of animals, and these patterns© Jones serve to distinguish& Bartlett the sourceLearning, Although LLC a human hair itself© has Jones no genomic & Bartlett DNA, Learning, LLC of the hair. (A) Cat hair, (B)NOT dog hair,FOR and SALE (C) sheep OR wool. DISTRIBUTIONit does contain mitochondrialNOT DNA. FOR The SALE follicular OR DISTRIBUTION tag can be used for DNA typing for either genomic or mitochondrial DNA. the forensic examiner may compare the samples on The catagenic phase is a short period of transi- the basis of the color, shape, and distribution of tion between the anagenic and telogenic phases. their© pigment Jones bodies & Bartlett and cortical Learning, fusi. LLC It lasts only© 2 Jonesto 3 weeks. & Bartlett During thisLearning, phase, hair LLC IfNOT hair FORhas been SALE dyed, OR dye DISTRIBUTION may sometimes be continues toNOT grow, FOR but the SALE root bulbOR DISTRIBUTIONshrinks, takes observed in the cuticle and the cortex. If the hair on a club shape, and is pushed out of the follicle. has been bleached, the cortex will be devoid of pig- During the telogenic (final) phase, hair natu- ment granules (though it may have a yellow tint). rally becomes loose and falls out. Over a 2- to © Jones & BartlettThe cortex Learning, can be observed LLC with a compound © Jones6-month & period,Bartlett the Learning, hair is pushed LLC out of the fol- NOT FORmicroscope. SALE OR The DISTRIBUTION hair is usually mounted in a liquid NOTlicle, FOR causing SALE the OR hair DISTRIBUTION to be naturally shed. The

Forensic Applications of Microscopy: Hair 95

9781449691790_CH04_FINAL.indd 95 28/10/13 9:42 AM former connection, the dermal papilla, is no lon- A. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ger attached to the hair but is assimilated by the NOT FOR SALE OR DISTRIBUTION NOT FORfollicle. SALE OR DISTRIBUTION Hair Hair grows at a constant rate of approximately 1 cm per month. If the shed hair has grown after Inner Root Sheath bleaching or coloring, an estimate of the time since Arrector Pili Muscle © Jones & Bartlett Learning, LLCchemical treatment can ©be Jones established & Bartlett by assessing Learning, LLC NOT FOR SALE OROuter DISTRIBUTION Root Sheath the presence (or absence)NOT of colorFOR pigment SALE ORor dye DISTRIBUTION Sebaceous Gland in the cuticle and cortex. Dermal Papilla Comparison of Hair by Microscopy B. © Jones & Bartlett Learning, LLC When hair© Jones evidence & Bartlettis found Learning,at the scene LLC of a crime, the forensic examiner must first answer two NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Hair questions: (1) Is the hair human? and (2) does it match the hair of the suspect? Inner Root Sheath If the victim is covered with pet hair, a trained Arrector Pili Muscle forensic examiner should be able to distinguish © Jones & Bartlett Learning, LLC Outer Root Sheath© Jonesan &animal Bartlett hair fromLearning, a human LLC hair with little diffi- Sebaceous Gland NOT FOR SALE OR DISTRIBUTION Basal LaminaNOT FORculty. SALE To do ORso, the DISTRIBUTION examiner will look for matches in published reference photos and use micros- Germ Dermal Papilla copy to reveal details of the sample’s cuticle (i.e., scales), medullar ratio, and medullar pattern. As C. © Jones & Bartlett Learning, LLCmentioned earlier, these© characteristicsJones & Bartlett are often Learning, LLC unique to a particular species. NOT FOR SALE OR DISTRIBUTIONHuman hair comparisonNOT FORis a much SALE more OR dif DISTRIBUTION- Hair ficult task. An examiner typically uses a comparison microscope to view the evidence hair and Inner Root Sheath Arrector Pili Muscle the known hair side by side. First, the examiner assesses the samples’ color, length, and diameter. © Jones & Bartlett Learning, LLCOuter Root Sheath © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Next, theNOT examiner FOR SALEcompares OR features DISTRIBUTION such as the Sebaceous Gland shape of the medulla (if present) and the distri- Dermal Papilla Germ bution, color, and shape of the pigment granules (including whether the hair has been colored or FIGURE 4-14 The three phases of hair growth are (A) the ana- bleached). Other abnormalities due to disease, fun- © Jones & Bartlettgen phase, Learning, (B) the catagen LLC phase, and (C) the telogen phase.© Jonesgal &infections, Bartlett or Learning, physical damage LLC can also be used NOT FOR SALE OR DISTRIBUTION NOT FORas a basisSALE for OR comparison DISTRIBUTION if found in a specimen. The microscopic comparison of human hair has been long accepted by the forensic community © M. Kaleb/Custom Medical Stock Photo Stock Medical Kaleb/Custom M. © as a valid way to include and exclude suspect hairs © Jones & Bartlett Learning, LLCagainst reference hairs—but© Jones only &if theBartlett examiner Learning, LLC NOT FOR SALE OR DISTRIBUTIONhas the proper trainingNOT to make FOR this SALE determina OR DISTRIBUTION- tion. In 2002, a study by the FBI reported that significant error rates were associated with the microscopic comparison of human hairs (Houck & Budlowe, 2002). As part of this study, human © Jones & Bartlett Learning, LLC hair evidence© Jones submitted & Bartlett to the Learning, FBI over a LLC4-year NOT FOR SALE OR DISTRIBUTION period NOTwas subjectedFOR SALE to bothOR DISTRIBUTIONstandard microscopic examination and DNA analysis. Of the 80 hairs compared, only 9 (approximately 11%) for FIGURE 4-15 The follicular tissue may potentially include DNA, which the FBI examiners found a positive micro- © Jones & Bartlettsuch as with Learning, this forcibly removedLLC head hair with follicular © Jonesscopic & Bartlett match between Learning, the questioned LLC sample and tissue attached. NOT FOR SALE OR DISTRIBUTION NOT FORa reference SALE hairOR wereDISTRIBUTION found not to match by DNA

96 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 96 28/10/13 9:42 AM Courtesy of Sirchie Fingerprint Laboratories. Fingerprint Sirchie of Courtesy The search for hair evidence should begin as © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC soon as it is possible. Hair evidence is easily trans- NOT FOR SALE OR DISTRIBUTION NOTferred FOR to SALE and from OR theDISTRIBUTION crime scene, perpetrator, and victim. Waiting too long to begin the search will bring into question the actual relationship of the evidence to the crime. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONInformation ObtainedNOT by Microscopic FOR SALE OR DISTRIBUTION Comparison of Hair FIGURE 4-16 Hairs can be collected using tape or a special A microscopic examination of the hair sample may vacuum. enable the examiner to determine the area of the © Jones & Bartlett Learning, LLC body from which© Jones the hair& Bartlett originated. Learning, Scalp hairs, LLC NOT FOR SALE OR DISTRIBUTION for example,NOT tend FOR to have SALE a consistent OR DISTRIBUTION diameter analysis. This study has led police and the courts and a relatively uniform distribution of pigment; to regard microscopic hair comparisons as subjec- in some cases, they may also be dyed, bleached, or tive; thus positive microscopic hair examinations damaged. By contrast, beard hairs may be relatively must be confirmed by DNA analysis before they coarse due to constant trimming and tend to have © Jones &will Bartlett be accepted Learning, as evidence LLC in court. Microscopic © Jonesblunt tips & Bartlett from cutting Learning, or shaving; LLC an examination NOT FORexamination SALE OR of DISTRIBUTION hair is, however, a fast and reliable NOTof FORa cross SALE section OR of DISTRIBUTION such a hair may reveal that technique for excluding questioned hairs from fur- it is triangular in nature. Pubic hairs, by compari- ther scrutiny. son, have widely variable cross-sections and shaft diameters; these short, curly hairs also may feature Collecting Hair Evidence© Jones & Bartlett Learning, continuousLLC medullae. © Jones & Bartlett Learning, LLC Hair evidence shouldNOT be collected FOR SALE by hand, OR using DISTRIBUTION a Microscopic examinationNOT cannot FOR reveal SALE the ageOR DISTRIBUTION bright light to illuminate the area being searched. or sex of the individual who was the source of a par- Hair evidence can be collected using a wide, trans- ticular hair. The exception is infant hair; it tends to parent sticky tape, lint roller, or a special evidence be short, with fine pigment granules. Sometimes, vacuum cleaner ( FIGURE 4-16 ). Strands of hair found microscopic analysis may be able to suggest the as evidence© Jones should & Bartlett be individually Learning, packaged LLC in race of the ©hair’s Jones owner. & Bartlett TABLE 4-1 Learning, lists the char LLC- paperNOT packets. FOR If SALEthe hairs OR have DISTRIBUTION been collected on acteristics ofNOT human FOR hair SALE that are OR associated DISTRIBUTION with tape, the entire lint roller or sticky tape should be particular racial groups. Head hairs are usually the packaged, complete with attached hair evidence, in best samples for determining race, although hairs a polyethylene storage bag. from other body areas can prove useful as well. © Jones & BartlettControl Learning,(reference) LLCsamples should be col- © JonesRacial determination& Bartlett Learning, from the microscopic LLC exami- NOT FORlected SALE from OR the DISTRIBUTION victim, the suspect, and any other NOTnation FOR of SALE head hairsOR DISTRIBUTIONfrom infants can be difficult, individual who could have left hair evidence of however, given the rudimentary nature of hair in his or her presence at the crime scene. Reference young children. Hairs from individuals of mixed hairs should be taken from all pertinent regions racial ancestry may possess microscopic charac- of the body. Fifty head hairs, taken from different teristics attributed to more than one racial group. regions of the head, ©should Jones be &plucked Bartlett (hair Learning, with DNA LLC studies have shown that© Jones many people& Bartlett have Learning, LLC roots is to be preferred)NOT or FORcut close SALE to the OR root. DISTRIBUTION In DNA from multiple racial groups;NOT FORthus race SALE cannot OR DISTRIBUTION sexual assault cases, 24 pubic hairs also should be be divided into clearly defined categories, as many plucked or cut close to the root. people falsely believe. The identification of race is

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC TABLE 4-1 NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Characteristics of Human Hair Race Diameter Cross Section Pigmentation Cuticle Undulation Negroid 69–90 µm Flat Dense and clumped — Prevalent Caucasian 70–100 µm Oval Evenly distributed Medium Uncommon © Jones &Mongolian Bartlett90–120 Learning, µm LLC Round Dense© Jonesauburn & BartlettThick Learning, LLCNever NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Forensic Applications of Microscopy: Hair 97

9781449691790_CH04_FINAL.indd 97 28/10/13 9:42 AM most useful as an investigative tool, but it also can An investigator must, therefore, be extremely care- © Jones & Bartlett Learning, LLC © Jones & Bartlettbe an associative Learning, tool LLC when an individual’s hairs ful to secure all fiber evidence so it will not be NOT FOR SALEexhibit OR unusual DISTRIBUTION racial characteristics. NOT FORaccidentally SALE ORlost DISTRIBUTIONand make certain to avoid any cross-contamination. Most fiber evidence allows the examiner only Forensic Applications of to place it within a class. Not until a suspect has Microscopy:© Jones Fibers & Bartlett Learning, LLCbeen identified and reference© Jones fibers & collected Bartlett from Learning, LLC NOT FOR SALE OR DISTRIBUTIONthis individual will fiberNOT evidence FOR SALEbe individual OR DISTRIBUTION- The term fiber is used to designate any long, thin, ized. The forensic examiner should begin the solid object. In scientific terms, a fiber is said to examination of fiber evidence with a low-power have a high aspect ratio; that is, the ratio of its stereoscopic microscope. This technique allows length to its cross-section diameter is large. Fibers the specific fibers in question to be selected and © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC of forensic interest are classified based on their ori- isolated for more detailed analysis. ginNOT and FOR composition SALE OR( FIGURE DISTRIBUTION 4-17 ). Most fibers of NOT FOR SALE OR DISTRIBUTION forensic interest are very common and are encoun- tered daily in homes and workplaces. Natural Fibers Investigators do not have to worry about the Items of clothing, remnants of cloth, thread or © Jones & Bartlettcomposition Learning, of fibers LLC being altered over time© Jonesyarn, & Bartlettand pieces Learning, of rope are LLC all commonly found NOT FOR SALEbecause OR the DISTRIBUTION vast majority of fibers do not undergoNOT FORat crime SALE scenes, OR DISTRIBUTIONand many are made from natu- physical, biological, or chemical degradation while ral fibers. Natural fibers, which are derived from at a crime scene. If one part of the fiber in question plant or animal sources, include materials such as has been damaged, microscopic measurements can cotton, flax, silk, wool, and kapok. In most textile usually be taken at many other points along the materials, the natural fibers are twisted or spun fiber. Because fibers© Jones are so & small Bartlett and light,Learning, they LLCtogether to form threads© orJones yarns &that Bartlett are woven Learning, LLC are easily transferredNOT fromFOR one SALE object OR to DISTRIBUTIONanother. or knitted into fabric.NOT When FOR examined SALE ORunder DISTRIBUTION As a consequence, they often provide evidence of magnification, a thread made from natural fibers association between a suspect and a crime scene. appears to be a collection of many small twisted Of course, if a fiber was transferred once during a hairs ( FIGURE 4-18 ). crime,© Jones it may & beBartlett easily transferred Learning, a secondLLC time— Cotton© Jones (a plant & fiber) Bartlett is the Learning, most widely LLC used such as during the investigation of the crime scene. natural fiber. In fact, undyed white cotton is so NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Fibers

Animal Vegetable Mineral Organic Inorganic © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Hair Silk Asbestos Synthetic Natural Metal Ceramic Glass Polymers Polymers

Polyolefin Polyester Nylon Acrylic Acetate Rayon Lyocell © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC FIGURE 4-17 The classification of fibers. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

98 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 98 28/10/13 9:42 AM © Phototake/Alamy Images Phototake/Alamy © form a thread or yarn. Whether the thread is a fila- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ment or a spun yarn can be determined simply by NOT FOR SALE OR DISTRIBUTION NOTuntwisting FOR SALE the yarn.OR DISTRIBUTIONFilament yarns unravel into long strands of fibers, whereas spun yarns unravel into short lengths of fiber that can be easily pulled apart. Because yarn is made by twisting parallel © Jones & Bartlett Learning, fibersLLC together, the twist direction© Jones is another & Bartlett factor Learning, LLC NOT FOR SALE OR DISTRIBUTIONthat allows for comparison.NOT Other FOR physical SALE prop OR- DISTRIBUTION erties used to compare yarn samples include their texture, the number of twists per inch, the number of fibers making up each strand, the blend of fibers (if more than one is present), the color, and pilling © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC characteristics (i.e., tufts of fiber sticking out of the NOT FOR SALE OR DISTRIBUTION main bundle).NOT FOR SALE OR DISTRIBUTION FIGURE 4-18 Threads made of natural fibers appear to be a The examination of threads of yarn is normally collection of many small fibers. done under a stereomicroscope using fine tweezers. The specimen is unraveled slowly and its fea- © Jones & Bartlett Learning, LLC © Jonestures noted & Bartlett while being Learning, viewed underLLC low power. NOT FORwidely SALE used OR inDISTRIBUTION clothing and other fabrics that it NOT FOR SALE OR DISTRIBUTION has almost no evidentiary value. Animal fibers include hair from sheep (wool), goats (cashmere), Woven Fabrics llamas, and alpacas as well as fur from animals Woven fabrics are made by intertwining two sets such as rabbits and mink. Identification of animal of yarns that are placed at a 90° angle to each other © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC fur follows the same procedure as the microscopic on a loom. The lengthwise strand, which is known examination of animalNOT hair FOR described SALE previously. OR DISTRIBUTIONas the warp, runs the lengthNOT of the FOR fabric. SALE The weft OR DISTRIBUTION strands are interlaced at right angles to the warp strands. The device used to weave fabrics is called Yarn a loom ( FIGURE 4-19 ). A loom can produce a variety Yarns© are Jones categorized & Bartlett into two Learning, primary groups: LLC fil- of distinctive© patterns,Jones &known Bartlett as weave Learning, structure. LLC amentNOT and FORspun. FilamentSALE OR yarns DISTRIBUTION are made of a con- The basicNOT weave FOR patterns, SALE which OR DISTRIBUTIONcan be seen in tinuous length of a human-made fiber. Spun yarns FIGURE 4-20 , are plain, satin, basket, twill, and leno. are made of short lengths of fibers that are twisted The plain weave is the most common weave struc- or spun together so they adhere to each other to ture ( FIGURE 4-21 ); each weft yarn goes alternately

Hair and fiber analysis provides a challenge when determine whether a hair fiber found at a crime scene questioned and known samples are similar but can- belongs to a person who has spent a significant pe- not be proved identical© Jones through ¤t Bartlett conventional Learning, riod LLC of time in the region or if ©it belongsJones to & someone Bartlett Learning, LLC methods. A new set NOTof methods FOR using SALE stable OR isotopes DISTRIBUTION who was merely passing through.NOT Likewise, FOR SALEclothing OR DISTRIBUTION is currently being examined for its ability to pro- fibers will show specific isotopic ratios depending on vide quantitative comparison data even in situations either the location of plant growth or the chemical in which today’s tools provide only qualitative data process through which the artificial fibers were made. (such© Jones as hair follicles& Bartlett without Learning, tags). LLC A caveat© to Jones this new & setBartlett of methods: Learning, The vari -LLC NOTIsotopic FOR forensics SALE depends OR DISTRIBUTION on the idea that the ability of isotopicNOT values, FOR even SALE within OR a homogeneousDISTRIBUTION keratinized components of the body (nails and hair) population, makes specific identification nearly im- are formed from the by-products of the food and water possible. Like many of the tests described in this that the person has consumed. Regional differences in book, isotopic analysis will be used more often to the isotopic composition of hair fibers can be used to exonerate suspects than to prosecute them. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Forensic Applications of Microscopy: Fibers 99

9781449691790_CH04_FINAL.indd 99 28/10/13 9:42 AM Reed © Jones & Bartlett Learning,Heddle LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Shuttle with Bobbin

Roll of Fabric

Pedals

over and under the warp yarns to produce a dura- two or more warp threads are interlaced with two ble “checkerboard”© Jones fabric. The& Bartlett twill weave Learning, creates LLCor more weft threads ( © FIGURE Jones 4-22 &). BartlettDenim fabric Learning, LLC a fabric with a diagonallyNOT FOR oriented SALE pattern OR DISTRIBUTION because is one of the most commonNOT FORtwill SALEweaves. OR Twill DISTRIBUTION fabric is distinctive because the two sides of the Plain Basket fabric look different. The satin weave produces a smooth fabric because four or more warp threads are allowed to “float” over the weft threads before © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Warp

Lengthwise

FIGURE 4-21 In this graphic representation of a plain weave, © Jones & Bartlett FIGURE 4-20 Learning, The most common LLC weave structures: plain, bas-© Jonesthe & red Bartlett squares are Learning,the warp yarn, andLLC the purple squares are ket, satin, twill, and leno. the weft yarn. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

100 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 100 28/10/13 9:42 AM Steep Synthetic Fibers © Jones & Bartlett Learning,63° LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOTRayon, FOR the SALE first human-madeOR DISTRIBUTION fiber, was introduced in the United States in 1910. The “wash and wear” Regular 45° revolution in the 1950s found Americans replacing their clotheslines with electric clothes dryers. The new wash-and-wear garments were made of acrylic © Jones & Bartlett Learning, andLLC polyester fibers, which ensured© Jones that & theyBartlett dried Learning, LLC Reclining NOT FOR SALE27° OR DISTRIBUTIONwrinkle free. Since then, a wideNOT variety FOR of SALE synthetic OR DISTRIBUTION fibers have replaced natural fibers in many fabrics, garments, rugs, and other domestic products. Today, the U.S. fiber industry produces more than © Jones & Bartlett Learning, LLC 9 billion pounds© Jones of fiber & eachBartlett year andLearning, has annual LLC NOT FOR SALE OR DISTRIBUTION domestic salesNOT that FOR exceed SALE $10 billion. OR DISTRIBUTION Modern manufactured fibers are classified into two categories: cellulosic fibers and synthetic fibers. Cellulosic fibers are produced from cellulose- containing raw materials, such as trees and other © Jones & Bartlett Learning, LLC © Jonesplants. &Synthetic Bartlett fibers Learning, are produced LLC from chemi- NOT FOR SALE OR DISTRIBUTION NOTcals FOR made SALE from refinedOR DISTRIBUTION petroleum or natural gas. The U.S. Federal Trade Commission (FTC) has approved generic names for each fiber type. For example, generic names for cellulosic fibers include © Jones & Bartlett Learning, rayon,LLC acetate, and lyocell; ©generic Jones names & Bartlett for syn- Learning, LLC NOT FOR SALE OR DISTRIBUTIONthetic fibers include polyester,NOT nylon, FOR acrylic, SALE poly OR- DISTRIBUTION olefin, and spandex. TABLE 4-2 lists generic fiber types, the most common trademarked names, and the major uses for each fiber type. Under the Textile Products Identification Act, the FTC imposes © Jones & Bartlett Learning, LLC criminal sanctions© Jones against & Bartlett anyone whoLearning, sells a tex LLC- NOT FOR SALE OR DISTRIBUTION tile fiber productNOT FORthat is SALE misbranded OR DISTRIBUTION or falsely or deceptively advertised. The earliest synthetic fibers were made by treating cotton or wood with a variety of chemicals FIGURE 4-22 The twill pattern can be at different angles, such © Jones &as Bartlettin this 3-1 twill Learning, pattern. LLC © Jonesto produce & Bartlett regenerated Learning, fibers. InLLC these processes, NOT FOR SALE OR DISTRIBUTION NOTcellulose FOR SALE is extracted OR DISTRIBUTIONfrom the cellulosic fiber, and the resulting material is immersed in a solvent. This thick liquid is then forced through a small hole, being tied down with one thread. In the satin causing the solvent to evaporate and a fiber to form. weave, the front of the fabric is composed almost In 1940, only 10% of the fibers used in the entirely of warp threads© Jones produced & Bartlett by repeating Learning, United LLC States were synthetic.© AfterJones World & Bartlett War II, Learning, LLC the weave. The satin NOTweave FOR is used SALE for satin OR fabric, DISTRIBUTION however, chemists at DuPontNOT learned FOR how SALE to create OR DISTRIBUTION cotton bed linens, and lingerie. Satin weave is very synthetic fibers using chemicals that are by-prod- flexible, which makes it useful for garments that ucts of petroleum refinement. Their discoveries led need to drape. to an explosion of new development in this area. Fabric analysis is usually performed under a The evolution of the technology to make these new stereomicroscope© Jones & Bartlettin conjunction Learning, with tweezers, LLC a © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION fibers proceededNOT handFOR inSALE hand ORwith DISTRIBUTION the develop- ruler for counting threads, and a protractor for ment of the plastics industry. measuring angles. The forensic examiner records the colors of the threads and number of threads per inch and determines the type of weave present Polymers © Jones &in Bartlettthe cloth. Learning, The questioned LLC fabric then is com- © JonesPlastics & are Bartlett malleable Learning, materials LLCthat can be easily NOT FORpared SALE to knownOR DISTRIBUTION textile samples. NOTformed FOR intoSALE a wide OR varietyDISTRIBUTION of products—sheets of

Forensic Applications of Microscopy: Fibers 101

9781449691790_CH04_FINAL.indd 101 28/10/13 9:42 AM © Jones & BartlettTABLE Learning, 4-2 LLC © Jones & Bartlett Learning, LLC NOT FOR SALESynthetic OR FibersDISTRIBUTION NOT FOR SALE OR DISTRIBUTION Generic Fiber Type Common Trademark Names Major Uses Acetate Celanese Acetate® Sportswear, lingerie, draperies, and upholstery Acrylic Cresloft®, Creslan®, Dralon®, Acrilan®, Sportswear, sweaters, socks, blankets, carpets, draperies, Duraspun®, Wear-Dated® and upholstery Lyocell © JonesTencel®, Lyocell& Bartlett by Lenzing® Learning, LLC Men’s and women’s dress ©clothing Jones & Bartlett Learning, LLC Nylon NOTCondura®, FOR Supplex®,SALE ORTactel®, DISTRIBUTION Antron® Ski apparel, windbreakers,NOT luggage, FOR rope, SALE tents, and OR DISTRIBUTION Zeftron®, Vivana®, Caprolan®, Capima® thread Polyester Dacron®, CoolMax®, Thermax®, Hollofil®, Permanent-press garments, ties, dress apparel, lingerie, Thermoloft®, Fortrel®, ESP®, Polarguard® draperies, sheets, and pillow cases Polyolefin Herculon®, Innova®, Marvess®, Salus®, Pantyhose, knitted sportswear, carpets, upholstery, © Jones & BartlettTelar®, Learning, Alpha Olefin®, LLC Essera®, Kermel® furniture,© Jones and slipcovers & Bartlett Learning, LLC NOTRayon FOR SALEModal® OR DISTRIBUTION Coat linings,NOT lingerie,FOR SALE ties, bedspreads, OR DISTRIBUTION and tablecloths Spandex Lycra®, Dorlastan® Bathing suits, lingerie, and stretch pants Data from American Fiber Manufacturers Association, Fabric University (www.fabriclink.com).

© Jones & Bartlettsandwich Learning, wrap, door LLC panels of cars, food contain©- Jonesand & dirt. Bartlett Octagonal-shaped Learning, LLCfibers offer glitter-free NOT FOR SALEers, or OR flexible DISTRIBUTION threads. Chemists call plastics polNOT- FOReffects. SALE Not surprisingly,OR DISTRIBUTION the forensic examiner may ymers because these huge molecules are formed be able to use these characteristics to place a syn- by chemically linking together many smaller mol- thetic fiber within a particular class. ecules. Polymer is derived from a combination of Companies may use a variety of techniques to the Greek words ©poly Jones (meaning & Bartlett “many”) Learning, and meros LLCdye fibers—sometimes even© Jones using &different Bartlett dyeing Learning, LLC (meaning “parts”).NOT The FOR individual SALE parts OR thatDISTRIBUTION com- NOT FOR SALE OR DISTRIBUTION bine to form the polymer are known as monomers A. Homopolymer (from the Greek monos, meaning “single”). In homopolymers (from the Greek homos, meaning “same”), one type of molecule is joined to other molecules© Jones of & the Bartlett same type Learning, to form an LLC enormously © Jones & Bartlett Learning, LLC B. Copolymers longNOT linear FOR thread;SALE ORan exampleDISTRIBUTION is polyethylene NOT FOR SALE OR DISTRIBUTION ( FIGURE 4-23A ). By changing the chemical structure Alternating of the monomer, different types of polymer chains can be easily assembled, each of which has different Random © Jones & Bartlettphysical Learning,properties. Copolymers LLC are formed by the© Jones & Bartlett Learning, LLC NOT FOR SALEreaction OR of DISTRIBUTION two different monomers ( FIGURE 4-23B NOT). FORBlock SALE OR DISTRIBUTION

Forming Synthetic Fibers Graft Most synthetic fibers are produced by the melt spinning process.© First, Jones the polymer& Bartlett is melted. Learning, The LLC © Jones & Bartlett Learning, LLC molten material isNOT then FOR forced SALE (extruded) OR DISTRIBUTION through NOT FOR SALE OR DISTRIBUTION a spinneret, a mold containing a variable number of holes ( FIGURE 4-24 ). As it cools, the polymer hardens into a solid. The shapes of the holes in the spinneret determine© Jones the cross-sectional & Bartlett Learning, shape of the LLC polymer— © Jones & Bartlett Learning, LLC forNOT example, FOR SALE round, OR trilobal, DISTRIBUTION flat, or dumbbell NOT FOR SALE OR DISTRIBUTION ( FIGURE 4-25 ). Round (hollow) fibers trap air, creating insulation (e.g., in synthetic down comforters). Tri- FIGURE 4-23 (A) Polyethylene is a homopolymer; it is a chain lobed fibers reflect more light, so they are often used of the single polymer polyolefin. (B) Nylon and polyethylene © Jones & Bartlettto give an Learning, attractive sparkle LLC to textiles. Pentagonal-© Jonesterephthalate & Bartlett (PET) Learning, are copolymers; LLC that is, they are made by the combination of different monomers. NOT FOR SALEshaped OR fibers, DISTRIBUTION when used in carpet, show less soilNOT FOR SALE OR DISTRIBUTION

102 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 102 28/10/13 9:42 AM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

FIGURE 4-24 The melted polymer cools and hardens to form a solid after it is forced through the spinneret.

techniques for the same© Jones fiber. If & pigments Bartlett are Learning, used microscope, LLC paying special© attention Jones &to Bartlett features Learning, LLC to color the fiber, theyNOT will FOR be attached SALE to OR the DISTRIBUTION sur- such as color, diameter, cross-sectionNOT FOR shape,SALE pit OR- DISTRIBUTION face as granules. In contrast, dyes will penetrate ting or striations, and the presence of dulling agents farther into the fiber. Many fibers have treated sur- ( FIGURE 4-26 ). The main advantages of microscopic faces. For example, shiny fibers may be treated comparison are as follows: with© dulling Jones agents, & Bartlett such as Learning, titanium dioxide, LLC to ● This technique© Jones does & notBartlett destroy Learning, the fiber, unLLC- makeNOT the fibersFOR appear SALE less OR lustrous. DISTRIBUTION like otherNOT analysis FOR techniques. SALE OR DISTRIBUTION ● Microscopic comparison is not limited by the Comparison and Identification sample size; a fiber 1 mm in length can be eas- of Synthetic Fibers ily examined. © Jones &The Bartlett first step Learning, in the comparison LLC of synthetic fibers © Jones● Every & Bartlett forensic laboratory Learning, has LLC a comparison mi- NOT FORis SALE an examination OR DISTRIBUTION of the fibers with a comparison NOT FORcroscope SALE readily OR available.DISTRIBUTION

Forensic Applications of Microscopy: Fibers 103

9781449691790_CH04_FINAL.indd 103 28/10/13 9:42 AM along the length of the fiber, which gives the fiber Man-Made Fibers © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC not only strength but also the ability to refract NOT FOR SALE OR DISTRIBUTION NOT FORlight. SALE Synthetic OR fibers,DISTRIBUTION which tend to be thicker in the center and thinner toward the edges, may therefore act as lenses. If the fiber’s refractive index is higher than that of the surrounding medium, the © Jones & Bartlett Learning, LLCrays converge toward the© Jonescenter of & the Bartlett fiber; if Learning, its LLC Round NOT FOR SALETr ilobal OR DISTRIBUTIONrefractive index is lowerNOT than thatFOR of SALE the surround OR DISTRIBUTION- ing medium, the rays diverge toward the edge of the fiber. The internal reflection of light within the fiber is due to the presence of minute differences in the solid state of the fiber. The forensic exam- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC iner can identify the refractive index of a fiber by NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Flat Dumbbell immersing the fiber in a fluid with a comparable refractive index and observing the disappearance FIGURE 4-25 The spinneret can be replaced with different- of the Becke line (the bright line that develops as shaped holes to make fibers with different cross sections. the objective lens is moved out of focus) under a © Jones & Bartlett Learning, LLC © Jonespolarizing & Bartlett microscope. Learning, This LLC technique is not lim- NOT FOR SALE OR DISTRIBUTION NOT FORited bySALE sample OR size, DISTRIBUTION and it is nondestructive.

Paint © Jones & Bartlett Learning, LLCCrime labs analyze a large© Jones number & of Bartlett paint chips. Learning, LLC NOT FOR SALE OR DISTRIBUTIONPaint is transfer evidence,NOT and itFOR can provideSALE imporOR DISTRIBUTION- tant clues in investigations, especially in burglaries and vehicular crimes. Paints are applied to many surfaces in our modern society, either because they protect the underlying material or for aesthetic pur- © Jones & Bartlett Learning, LLC poses where© Jones a beautiful & Bartlett surface Learning, is desired. Water-LLC NOT FOR SALE OR DISTRIBUTION based andNOT oil-based FOR SALEpaints areOR composed DISTRIBUTION of three FIGURE 4-26 Color, texture, shape, and surface features are all major ingredients: (1) a pigment, (2) a solvent, and used as bases on which to compare fibers. (3) a binder. The pigment, either organic or inorganic, pro- © Jones & Bartlett Learning, LLC © Jonesvides & Bartlettthe desired Learning, color. The LLC primary pigment in Once the microscopic comparison has shown that NOT FOR SALE OR DISTRIBUTION NOT FORwhite SALE paint ORis inorganic, DISTRIBUTION usually titanium oxide the gross morphology of the two fibers is the same, (TiO2) or zinc oxide (ZnO). These compounds are the chemical composition of the samples is com- white or opaque, and they serve to cover any previ- pared. Additional tests should be performed to ous color on the surface to be painted. White lead

determine whether the fibers belong to the same [2 PbCO3 ∑ Pb(OH)2] was used extensively as a generic class. Additionally,© Jones &the Bartlett analyst shouldLearning, try LLCprimary pigment until 1977,© Jones when & it Bartlett was banned Learning, LLC to place the fiberNOT into aFOR specific SALE polymer OR DISTRIBUTIONsubclass. for interior use because NOTof its FORtoxicity. SALE Pigments— OR DISTRIBUTION

(Recall the earlier example, in which a fiber was such as carbon black, iron oxide (Fe2O3, brown first classified as a nylon, and then further classi- and red), cadmium sulfide (CdS, orange), chro-

fied as nylon-6 versus nylon-6,6.) mium oxide (Cr2O3, green), and various organic © JonesThe refractive & Bartlett index Learning, is another useful LLC physical compounds—are© Jones mixed& Bartlett with the Learning, primary pigment LLC property that can be used for the identification of NOT FOR SALE OR DISTRIBUTION to obtainNOT the FORdesired SALE color. ORBlue DISTRIBUTION and green colors synthetic fibers. As mentioned earlier, synthetic are made by adding organic pigments. fibers are manufactured by drawing a molten poly- The solvent in a paint is the liquid in which meric substance through a spinneret to create a the pigment, binder, and other ingredients are sus- fiber. The force exerted during this extrusion pro- pended, usually in the form of an emulsion. Once © Jones & Bartlettcess causes Learning, the molecules LLC in the polymer to align© Jonesthe & paint Bartlett has been Learning, spread, theLLC solvent evaporates NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

104 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 104 28/10/13 9:42 AM and the paint dries. In oil-based paints, the solvent iStockphoto/Thinkstock © © Jones & Bartlett Learning, LLC © Jones is& usuallyBartlett a mixture Learning, of hydrocarbons LLC obtained from NOT FORpetroleum. SALE OR A DISTRIBUTIONcompatible organic solvent must be NOT FOR SALE OR DISTRIBUTION used for thinning the paint and cleaning up after painting. This is usually turpentine, which, like most other suitable solvents, gives off hazardous fumes. In water-based© paints,Jones the & Bartlettsolvent is Learning,water, LLC © Jones & Bartlett Learning, LLC which can be used bothNOT for FOR thinning SALE and ORfor clean DISTRIBUTION- NOT FOR SALE OR DISTRIBUTION ing up. The binder is a material that polymerizes and hardens as the paint dries, forming a continuous film that holds the paint to the painted surface. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The pigment becomes trapped within the polymer network.NOT In FOR older SALE oil-based OR paints, DISTRIBUTION the binder was FIGURE 4-27 SeveralNOT layersFOR of SALEpaint are ORapplied DISTRIBUTION to automo- usually linseed oil. As the solvent evaporates and biles during the production process. the paint hardens, the linseed oil chemically reacts with atmospheric oxygen to form a cross-linked © Jones &polymeric Bartlett material. Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALEThe latexOR DISTRIBUTIONbinder in water-based paint is dis- NOTThe FOR next SALE layer of OR paint DISTRIBUTION is called the basecoat. This persed into the paint and starts to coalesce and layer, which is an acrylic-based polymer, gives the form a solid film as water evaporates. The slightly automobile its beautiful color. The basecoat might rubbery nature of the partially polymerized mate- also contain aluminum or metal oxide powders to rial explains why water-based paints are called give the paint a metallic look. Finally, an unpig- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC latex paints. As the water evaporates, further mented acrylic clearcoat is applied to provide polymerization occurs,NOT and FOR the paint SALE hardens. OR DISTRIBUTIONresistance to scratches, solarNOT radiation, FOR SALE and acid OR DISTRIBUTION Several synthetic polymers are used as binders rain. Not only is each layer a different color, but in latex and acrylic paints. Paints with poly (vinyl the organic resin and pigment in each layer are acetate) binders now account for about 50% of different. A careful analysis that reveals the layer the paint© Jones used for& Bartlettinterior work. Learning, Those withLLC poly- structure will© Jonesallow an & examiner Bartlett toLearning, individualize LLC styrene-butadieneNOT FOR SALE binders OR are DISTRIBUTION less expensive but the paint chip.NOT FOR SALE OR DISTRIBUTION do not adhere quite as well and have a tendency to yellow. Acrylic paints, made with acrylonitrile binders, are considerably more expensive than Collection of Paint Evidence other types of paints, but they are excellent for © Jones & Bartlett Learning, LLC © JonesPaint evidence & Bartlett is most Learning, likely to beLLC found in crimes exterior work. They adhere well and are washable, involving burglary or involving a vehicle. When NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION very durable, and resistant to damage by sunlight. a paint chip is located, the investigator must be In most respects, they are superior to oil-based extremely careful to keep the paint chip intact. Paint paints, which they have now largely replaced. chips can be handled with forceps or picked up by sliding a thin piece of paper under the chip. It is Automobile Paint© Jones & Bartlett Learning,best LLC not to attempt to remove© paintJones that & is Bartlett smeared Learning, LLC Automobile paint isNOT much FOR more SALE complicated. OR DISTRIBUTION on clothing or other objects.NOT The FORobject SALEshould ORbe DISTRIBUTION During the manufacturing of automobiles, several carefully packaged and sent to the laboratory. different layers of paint are applied ( FIGURE 4-27 ). A reference sample must be collected for com- Each layer has its own unique function. The electro- parison. This sample should always be collected coat ©primer Jones is an& epoxyBartlett resin Learning, that is applied LLC to the from an undamaged© Jones area& Bartlett for comparison Learning, in theLLC steel body of the car for corrosion resistance. This laboratory. When collecting a sample from a vehi- NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION primer is black or gray in color. Next, the primer cle involved in an accident, it is very important surfacer is applied to hide any minor imperfections that the collected paint be as close to the point of in the surface. This primer is an epoxy—modified impact as possible. Remember that not all surfaces polyester or polyurethane. Pigment is added to this of an automobile fade at the same rate, and parts of © Jones &primer Bartlett to cover Learning, and hide LLC the electrocoat primer. © Jonesthe car &may Bartlett have been Learning, repainted. LLC When collecting NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Collection of Paint Evidence 105

9781449691790_CH04_FINAL.indd 105 28/10/13 9:42 AM © Jones & Bartlett Learning. Photographed by Carolyn Arcabascio. Carolyn by Photographed Learning. Bartlett & Jones © © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION FIGURE 4-28 A jigsaw match is conclusive evidence. FIGURE 4-29 Color, texture, and layer sequence are easier to observe when using a microscope.

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALEan automotive OR DISTRIBUTION standard the investigator must NOTbe FORfrom SALE a known OR source. DISTRIBUTION Considering that there are careful to remove all the layers of paint (includ- thousands of paint colors, it is not surprising that ing the undercoat layers) down to the metal (or color is the most important forensic characteristic. plastic) body surface. This is easily accomplished The color, texture, and layer sequence can be eas- by using a sharp scalpel to remove the paint refer- ily observed by placing the questioned and known ence sample. If there© Jones was a & cross-transfer Bartlett Learning, of paint LLCsamples under a stereomicroscope© Jones &( FIGUREBartlett 4-29 )Learning, or LLC between two vehicles,NOT allFOR layers SALE of paint OR need DISTRIBUTION to be an illuminated desk magnifier.NOT FOR The layerSALE structure OR DISTRIBUTION removed from each vehicle. order, color, thickness, and other details should be In cases of burglary, tools used by the burglar recorded. It may be necessary to cut the paint chip may have trace paint evidence attached. If such a so that necessary information can be collected. tool© Jones is found, & Bartlettthe investigator Learning, should LLC package it Using a© scalpel Jones to &cut Bartlett through Learning, the chip can LLC help and send it to the laboratory for examination. A reveal the layer structure. Sometimes the chip is NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION reference paint sample should be collected from an cast into a block of epoxy, and microtome is used to area that has been in contact with the tool, such as cut the chip and reveal its layer structure. Samples a window sash or a doorjamb. Care must be taken embedded in epoxy make it possible to grind and to remove all the layers of paint down to the base polish the edge so that physical details such as pig- © Jones & Bartlettmaterial Learning,(e.g., wood, LLC plastic, aluminum). If there© Jonesment & Bartlettsize and distribution Learning, can LLC be determined. NOT FOR SALEare many OR coatsDISTRIBUTION of paint on the window or door thatNOT FOR IfSALE the paint OR chipsDISTRIBUTION are big enough, destructive was the point of entry for the burglar, these paint chemical tests on a part of the chip can provide chips may have unique layers. additional data. The application of solvent to a An investigator needs to be very careful when paint chip will cause swelling or the generation handling paint evidence. A physical “jigsaw” match of colors. This information may help to identify © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ( FIGURE 4-28 ) of a questioned paint chip and an resins and pigments in the chip. These tests can be area where the referenceNOT FOR paint SALE is being OR DISTRIBUTIONcollected performed in a porcelainNOT spot plateFOR with SALE very OR small DISTRIBUTION are conclusive evidence. The fit of the edges of the paint chips under a stereomicroscope. By compar- two (questioned and reference chips), any surface ing the reaction of the questioned and known sam- markings, and the layer structure will establish ples to different solvents, trained microscopists can the© Jones uniqueness & Bartlett of the match Learning, and will LLC individualize determine© Jonesif the two & cameBartlett from Learning, a common source.LLC theNOT match. FOR SALE OR DISTRIBUTION InfraredNOT microspectrophotometry FOR SALE OR DISTRIBUTION is routinely used for paint analysis. Any infrared beam is reflected Forensic Analysis of Paint from the surface of the paint chip to produce an infrared spectrum of the surface. The infrared Forensic paint analysis begins with a comparison spectra are then interpreted and compared with © Jones & Bartlettof the paint Learning, chip in LLCquestion and the paint chip© Jonesthe & infrared Bartlett spectra Learning, of known LLC organic materials. In NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

106 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 106 28/10/13 9:42 AM © 2010 PerkinElmer, Inc. All rights reserved. Printed with permission. with Printed reserved. rights All Inc. PerkinElmer, 2010 © © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION FIGURE 4-31 A paint chip can have many layers. FIGURE 4-30 The infrared spectrum of paint found on a prybar is identical to the infrared spectrum of paint at the crime scene, which strongly suggests that the prybar was at the © Jones &crime Bartlett scene. Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION this way, the identity of the major organic compo- power of the SEM, and the identity of the pigment nents present in the paint chip can be determined can be determined by the EDX. The chip is cast ( FIGURE 4-30 ). into an epoxy block and a side is cut away with a An SEM with an energy-dispersive© Jones & Bartlett X-ray Learning,(EDX) microtome.LLC FIGURE 4-31 shows© Jones a chip &standing Bartlett on Learning, LLC can be used to identify the inorganic pigments in end, with its layer structure exposed, giving a pic- NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION a paint sample. The layer structure can be stud- ture of not only the layers but also their elemental ied in more detail by using the high magnifying composition.

Forensic Analysis of Paint 107

9781449691790_CH04_FINAL.indd 107 28/10/13 9:42 AM © Jones & BartlettWRAP Learning, UP LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION YOU ARE THE FORENSIC SCIENTIST SUMMARY

1. The black ski mask© Jones is the same& Bartlett color as theLearning, ski mask worn LLC by the robber and probably© hasJones been used& Bartlett by him. ThisLearning, LLC mask should beNOT carefully FOR examined SALE for OR hair DISTRIBUTION or fiber evidence as well as any personalNOT hygiene FOR (e.g., SALE cologne, OR hair DISTRIBUTION gel) residues. The hair and fiber evidence should be characterized using the microscopic techniques described in this chapter. The personal hygiene residues are organic material. 2. A short, brown beard hair found inside the ski mask indicates the transfer of hair evidence. It is reasonable to as- © Jonessume that & a Bartlettman with this Learning, color of hair LLC wore the ski mask at some point.© Jones Although & theBartlett person withLearning, the brown LLC beard may not be the last person to put on the mask, it is reasonable that the police should follow this lead. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Chapter Spotlight © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE● The OR microscopic DISTRIBUTION techniques used to investigateNOT FOR● The SALE portions OR ofDISTRIBUTION a hair that are vital to forensic trace fiber and hair evidence focus on their mor- examination are the cuticle, cortex, and me- phology. The methods employed for morpho- dulla. These layers of the hair shaft may reveal logical comparisons of questioned and control important information about the source of the samples often are used to show that two samples hair (e.g., if it is human, whether it belongs to do not match,© ratherJones than & Bartlett that the Learning,individual LLC the suspect). © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION who left behind the questioned trace sample was ● At a crime scene, collection of hair and fiber evi- the same person who was the source of the con- dence can be done by using a vacuum with spe- trol sample. cialized filters and/or using lift tape. In the lab, ● The common types of microscopes used in collection of hair and fiber evidence can be done © processingJones & Bartletttrace evidence Learning, are the LLC compound by gently© Jones shaking & theBartlett evidence Learning, over white LLC paper NOTmicroscope, FOR SALE the comparisonOR DISTRIBUTION microscope, the and byNOT using FOR a vacuum SALE orOR lift DISTRIBUTION tape. Collection polarizing (optical) microscope, the microspec- of hair and fiber evidence from a body generally trophotometer, and the SEM. involves the use of lift tape.

● In addition to identifying the refractive index, ● Once a sufficient number of hairs have been col- © Jones & Bartlettwhich Learning, provides information LLC about fiber compo©- Jones lected& Bartlett (50 head Learning, hairs), these LLC hairs are compared sition, microspectrophotometry can be used to under a microscope, and the morphology is NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION analyze the composition of unknown materials, noted and matched to standards and unknown particularly dyes on fibers. samples from other sources.

● SEMs are capable of magnifying an object 10 to ● Fiber evidence can be classified as natural (e.g., 100,000 times. They are used to compare fiber cotton, flax, wool) or synthetic (e.g., polyester). © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC surface morphologies between samples and, ● Fibers are compared with standards provided by NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION when combined with EDX, provide composi- manufacturers when available. tional information.

108 CHAPTER 4 The Microscope and Forensic Identification of Hair, Fibers, and Paint

9781449691790_CH04_FINAL.indd 108 28/10/13 9:42 AM 28/10/13 9:42 AM http://criminaljustice.jbpub.com/Criminalistics3 Wrap Up 109 © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE A microscope that mea- Light that oscillates in only A microscope that illuminates Materials that have the same opti- Materials that have A layer of automobile paint that The lower lens of a microscope; the The lower lens of a microscope; the The part of the specimen that can be of the specimen The part The actual nonmagnified image. Tissue surrounding the hair shaft that Tissue surrounding A property of a substance in which it A property of a substance in which © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION The part of a microscope that illumi- The part of a microscope © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION One-millionth of a meter (µm). The upper lens of a microscope; the lens The upper lens of a microscope; the A lens that passes light waves that are os- A lens that passes light waves that A large organic molecule made up of re- Added to paint to give it color. The primary protein that forms hair and The primary protein A column of cells running down the center A column of cells the specimen with polarized light. adheres to hair when it is pulled out. adheres to hair when of the hair. peating units of smaller molecules (monomers). nates the specimen for viewing. nates the specimen sures the interaction of infrared or ultraviolet ra- sures the interaction of infrared or diation with a sample. cal properties when observed from any direction. cal properties when nails. lens closest to the specimen. nearest to the eye. one plane. shows different colors when exposed to polar- shows different colors when exposed ized light from different directions. slows corrosion of the underlying steel. seen through the microscope lenses. the microscope seen through cillating only in one plane. sotropic materials Ocular lens Pigment Plane-polarized light Pleochroism Polarizer Polarizing microscope Polymer Primer surfacer “Real” image Field of view Field of view Follicular tag Illuminator I Keratin Medulla Micrometer Microspectrophotometer Objective lens © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC & Bartlett Learning, © Jones SALE OR DISTRIBUTION NOT FOR LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. Two microscopes linked by A microscope with one body © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION An anisotropic material. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE Material that appears different Material that appears A solid without order in the ar- order in the A solid without First layer of paint applied to the The intermediate stage of hair Fibers that are produced from cel- Fibers that are produced The initial phase of hair growth, The initial phase The depth of the area of the speci- A lens under the microscope stage that A lens under the microscope stage - objec as the develops A bright line that Outermost layer of automobile paint that Outermost layer of automobile paint The layer of automotive paint that con- The layer of automotive A scale structure covering the exterior of A scale structure covering the exterior The material that hardens as the paint dries, The material that The body of the hair shaft. © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE Key Terms © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION tube that is used for magnification in the range of tube that is used for magnification 25 to 1200 times. the hair. tains the colored pigment. tains the colored an optical bridge. men that is in focus. forming a continuous film. rangement of its atoms. rangement focuses light on the specimen. lulose-containing raw materials, such as trees or lulose-containing raw materials, such other plants. when the direction of observation is changed. when the direction growth, which occurs between the anagenic and growth, which occurs between the telogenic phases. when the hair follicle is producing hair. when the hair follicle contains no pigment. steel body of an automobile. tive lens of a microscope is moved out of focus. tive lens of a microscope Anisotropic material Basecoat Becke line morphous material Amorphous Anagenic phase Depth of focus Electrocoat primer Condenser Cortex Cuticle Comparison microscope Compound microscope Cellulosic fibers Clearcoat Binder Birefringent material Catagenic phase

9781449691790_CH04_FINAL.indd 109

NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning, LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC 9781449691790_CH04_FINAL.indd 110

http://criminaljustice.jbpub.com/Criminalistics3 1 CHAPTER4 110 Fill intheBlank Spectroscopy Solvent Scanning electronmicroscope(SEM) Regenerated fibers Refractive index Refraction NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC 8. 6. 1. 2. 5. 9. 4. 7. 3. light bydifferentmaterials. vacuum toitsvelocityinanyothermedium. or woodwithavarietyofchemicals. paint aresuspended. electrons. that illuminatesthespecimenwithabeamof that are scope lensdoubles,itisabletoresolvedetails As thenumericalaperture(NA)ofamicro- pound microscopeisthe The upperlensintheeyepieceofcom- A magnifyingglassisa(n) in How muchlightbendsdependsonthechange that isthickerinthemiddlethanatedge. the The lower lens inacompoundmicroscope is a hollowtube. that areatfixeddistancesfromoneanotherin Putting ItAllTogether view As themagnifyingpowerincreases,fieldof A(n) up to A compoundmicroscopecanmagnifyobjects image isknownasthe When usingamagnifyingglass,themagnified the magnifyingglass. The liquidinwhichthecomponentsof The bendingoflightwaves. Measurement oftheabsorption A ratioofthevelocitylightina NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC Fibers madebytreatingcotton The Microscope andForensicIdentification ofHair,Fibers,andPaint asthelightentersandleaves lens. © Jones&Bartlett Learning,LLC.NOTFORSALE ORDISTRIBUTION. (increases/decreases). microscope has two lenses microscope has times. asclosetooneanother. A microscope image. lens. lens NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning, LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC Working distance Weft Warp Virtual image Telogenic phase Synthetic fibers Stereoscopic microscope 15. 11. 10. 14. 13. 12. 16. 17. through alens. being investigatedandtheobjectivelens. the specimenatlowormediummagnification. arate bodytubesthatallowbotheyestoobserve ing whichhairfallsoutofthefollicle. made fromrefinedpetroleumornaturalgas.

densed andfocusedthroughthe The light rays fromthe illuminator are con- the when usingacompoundmicroscopeiscalled The thicknessoftheregionthatisinfocus the specimenis The distancebetweentheobjectivelensand pieces. The microscope. best performedbyusinga(n) Side-by-side comparisonsofspecimensare lens. directions. posed topolarizedlightcomingfromdifferent in whichitshowsdifferentcolorswhenex- As thedirectionofobservationischanged, properties whenobservedfromalldirections. appearance. Crosswise strandsofyarnonaloom. Lengthwise strandofyarnonaloom. NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC An imagethatisseenonlybylooking The finalphaseofhairgrowth,dur- Fibers produced from chemicals Fibers produced The distancebetweentheobject materialswillchangetheir isthepropertyofasubstance materialshavethesameoptical . A microscope with two sep- A microscopewith microscopehastwoeye- NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC . 28/10/13 9:42 AM

28/10/13 9:42 AM http://criminaljustice.jbpub.com/Criminalistics3 . to . . crimes. Wrap Up 111 fibers. , and match. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE components of a paint chip. under the chip. -shaped synthetic fibers reflect synthetic fibers -shaped microscope. structure. and , © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION A unique fit of the edges of two paint chips is A unique fit of the edges of two paint called a(n) more light and give an attractive sparkle to sparkle and give an attractive more light textiles. comparing two synthet- The first step in the fibers with a(n) ic fibers is to examine the paint chips. Paint evidence important in is especially Paint chips can be picked up by sliding a piece Paint chips can be picked up by sliding of Synthetic fibers made from cellulose fibers are cellulose fibers fibers made from Synthetic as also known Other than color, what is the most important Other than color, what is the most physical property of a paint chip when making a comparison? Paints have three major components. They are Paints have three Destructive chemical tests can be carried out Destructive chemical tests can be on paint chips by applying Synthetic fibers can be identified by compar- Synthetic fibers can ing their Infrared microspectrophotometry will reveal Infrared microspectrophotometry the A reference paint sample can be obtained from A reference paint sample can be obtained an automobile by using a(n) a block of Sometimes a paint chip is cast into to reveal its epoxy and cut with a microtome 39. 32. 35. 37. 30. 36. 34. 42. 33. 41. 38. 31. 40. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC & Bartlett Learning, © Jones SALE OR DISTRIBUTION NOT FOR LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION

. , , . after the . , and © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. spectrum of the sample spectrum of the sample phase, hair becomes loose (catagenic/anagenic/telo- , and the © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE . . . , © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE and falls out. fabrics are The three most basic weaves in A spectrophotometer measures the light in- A spectrophotometer of tensity as a function can be measured. light has interacted with the sample. light has interacted The electrons that reflected are immediately source in a scanning back toward the electron are called electron microscope Cellulosic fibers are produced from raw Cellulosic fibers are produced contain materials from trees or plants that the electrons. the protein Hair is composed primarily of (cylindrical/patterned). known as The initial phase of hair growth is the The microspectrophotometer is an instrument is an instrument The microspectrophotometer a that attaches to spectrophotometer a(n) During the final phase of hair growth, known During the final phase of hair growth, as the genic) phase. The medulla of human hair is Synthetic fibers are produced from chemicals Synthetic fibers are produced from made from refined A human hair has three layers: the - the UV, visi With a microspectrophotometer, ble, and © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION 27. 20. 21. 28. 22. 25. 18. 26. 24. 29. 23. 19.

9781449691790_CH04_FINAL.indd 111

http://criminaljustice.jbpub.com/Criminalistics3 1 CHAPTER4 112 Review Problems True orFalse NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC 2. 1. 6. 5. 4. 3. 2. 1. label thediagram. man hairandacathair.Showallparts fers fromhumanhair.Drawadiagramofhu- with acat.Describeindetailhowcathairdif- which theMEtooksamplesinProblem1lived You learnfromawitnessthatthecorpse unit foranalysis? Which ofthehairsshouldbesenttoDNA the victim’sheadandclothes. evidence from how theMEshouldcollectandpreservehair corpse from a crimescene. Describe indetail The medicalexaminer(ME)isexamininga When obtainingareferencepaintsamplefrom comparison microscope. fibers isanexaminationofthewitha The firststepinthecomparisonofsynthetic 2 cmpermonth. Hair growsataconstantrateofapproximately by microscopichairanalysis. The ageoftheindividualcanbedetermined microscopic hairanalysis. The raceofthesuspectmaybeindicatedby termine fibersubgroups. Microspectrophotometers canbeusedtode- NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC The Microscope andForensicIdentification ofHair,Fibers,andPaint © Jones&Bartlett Learning,LLC.NOTFORSALE ORDISTRIBUTION. NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning, LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC 10. 4. 3. 9. 8. 7. date andthedayhedied? 0.25 cm.How much timeelapsed between this hair. Thebrownrootsofthehairmeasured mate rememberedthedayhelastbleachedhis he hadbrownhairrootsshowing.Hisroom- ly brownhair,regularlybleachedhisand wooded site.Theindividual,whohadnatural- A humanbodywasrecoveredfromaremote would yourecord? your analysis.Whichdetailsaboutthefabric ric. Describeindetailhowyouwouldperform You havebeenaskedtoexamineawovenfab- under astereomicroscope. paint chipcanbeeasilyobservedbyplacingit The color,texture,andlayersequenceofa pigment ineachlayer. ture ofapaintchipwillgivetheidentity Using anSEM-EDXtoanalyzethelayerstruc- any surfaceoftheautomobilebeingexamined. A referencepaintsamplecanbeobtainedfrom pigments. Blue andgreenpaintsaremadewithorganic should beremoved. an automobile,onlythetoplayerofpaint NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC NOT FORSALEORDISTRIBUTION © Jones&BartlettLearning,LLC 28/10/13 9:42 AM 28/10/13 9:42 AM http://criminaljustice.jbpub.com/Criminalistics3 Wrap Up 113 Forensic Science Commu- Forensic Science © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION 11(2). http://www.fbi.gov/about-us/lab/forensic- information for interpretation. for interpretation. information nications, science-communications/fsc/april2009/review/2009_04_ review02.htm. chemists, and conservators. Boca croscopy for criminalists, Raton, FL: CRC Press. of Justice. http://www.nij.gov/top - tice, U.S. Department ics/forensics/lab-operations/standards/scientific-working- groups.htm , (2nd ed., Vol. 2). erstein (Ed.), Forensic science handbook Prentice-Hall. Upper Saddle River, NJ: Answers to Review Problems Chapter Objectives Interactive Glossary Flashcards Crossword Puzzles Practice Quizzes CWS URL and list of features CWS URL and list of Oien, C. T. (2009). Forensic hair comparison: Background hair comparison: Background (2009). Forensic Oien, C. T. of mi T. (2004). Color atlas and manual- Petraco, N., & Kubic, Scientific Working Groups. (2012). National Institutes of Jus- Forensic paint examination. In R. Saf- Thornton, J. L. (2002). © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC & Bartlett Learning, © Jones SALE OR DISTRIBUTION NOT FOR LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. 6(1). http://www.fbi.gov/about- © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE © Jones & Bartlett Learning, LLC © Jones & Bartlett OR DISTRIBUTION NOT FOR SALE Further Reading Further © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION . E 2228-02 Standard of textile fibers in ASTM examination PA: Author. West Conshohocken, River, NJ: Prentice-Hall. R. Saferstein (Ed.), Forensic science tion of human hair. In Saddle River, NJ: Pren- handbook (2nd ed., Vol. 1). Upper tice-Hall. York: Taylor & Francis. manual for human hairs. Forensic 1: A practical guide and , Science Communications - us/lab/forensic-science-communications/fsc/jan2004/re search/2004_01_research01b.htm. In R. Saf- the forensic aspects of textile fiber examination. erstein (Ed.), Forensic science handbook (2nd ed., Vol. 2). Upper Saddle River, NJ: Prentice-Hall. Journal scopic and mitochondrial DNA hair comparisons. of Forensic Sciences, 47, 964. Standard guide for (2004). Standard guide ASTM International. microscopic (2nd ed.). Upper Saddle Bell, S. (2012). Forensic chemistry and associa- The forensic identification Bisbing, R. E. (2002). of glass and paint. New Caddy, B. (2001). Forensic examination S. L. (2000). Microscopy of hair—part Deedrick, D., & Koch, An introduction to Eyring, M. B., & Gaudette, B. D. (2005). of micro- Houck, M. M., & Budlowe, B. (2002). Correlation

9781449691790_CH04_FINAL.indd 113