Trace Evidence

Procedure Santa Ana Police Department 6101 Santa Ana PD Procedures Manual

TRACE EVIDENCE

6101.1 PURPOSE This procedure establishes guidelines for the proper identification and collection of trace evidence.

6101.2 INTRODUCTION Trace evidence is defined as small evidentiary particles and includes, but is not limited to, hair, fibers, glass fragmentation, paint transfers / chips, gun shot residue, fire debris, botanical material, soil, and unknown chemical solids or liquids. Locard’s Exchange Principle states that whenever two objects come into contact a transfer of material will occur. The transfer may be primary (direct) or secondary (indirect) and usually involves trace evidence. Personnel responsible for the collection of trace evidence at any crime scene shall adhere to the following guidelines. Their actions or inactions should be based upon the particulars of each crime scene and firmly rooted in accepted forensic practices.

6101.3 PROCEDURE FOR LOCATING/IDENTIFYING TRACE EVIDENCE The following methods for detecting trace evidence at crime scenes are acceptable. No one method is correct for any given circumstance and it is recommended that more than one, if not all, methods be used to locate potential trace evidence at a scene. 1. Using direct light can be a very effective way of locating trace evidence. The brighter the light source, the more likely the forensic investigator will notice subtle differences in color and contrast of adhering surface particles. 2. Oblique lighting takes advantage of differences in the reflective qualities of particles versus the reflective qualities of the surface on which the particles reside. This method works well under low ambient light conditions. 3. Magnification is always advantageous. This method differentiates between particles with similar gross appearances and for making visible particles, which would otherwise go unnoticed. 4. Use of an Alternate Light Source (ALS) is often useful for visualizing many otherwise invisible evidentiary particles at scenes. It is important to note that different wavelengths used in combination with various filters each may reveal something new and previously unnoticed. The forensic investigator is encouraged to try all combinations of wavelength and filter.

6101.4 DOCUMENTING TRACE EVIDENCE As with any item of evidence, it is imperative that thorough documentation through accurate note taking, sketching, diagramming and/or photography (with and without scale) take place prior to collection. Because trace evidence is small by nature, overall, midrange and close-up photographs depicting where the item is relative to other items in the scene is imperative. Close-up photographs of trace

TRACE EVIDENCE evidence should always fill the frame. Keep in mind that photographic filters may also become necessary to best document the evidence. Notes may include sketches and should be clear, concise and easily read by any viewer. Abbreviations should always be defined. Forensic Notes will become the foundation of your report and are susceptible to both peer review and later discovery.

6101.5 COLLECTING TRACE EVIDENCE In most instances, trace evidence should be collected prior to the collection of biological or fingerprint evidence, although there may be exceptions. Be aware of other forms of potential evidence that could be destroyed or altered because of the collection technique. The following techniques may be applied to the collection of trace evidence: 1. Hand Picking – Disposable or sanitized forceps, tweezers, and magnets, as well as gloved hands, can be used to remove some trace evidence, collecting the larger particles first. Magnification and a bright light sourceaid in this technique. Hand Picking is beneficial because, not only is it a one step process, but also it allows the forensic investigator the ability to document exactly where the particle(s) came from. Individually collected hairs and fibers may be placed on a clean “POST-IT” style paper or weigh paper for later packaging. 2. Tape Lifts - Using manufactured Tape Lifts or a roll of clear “inspected” sealed tape that is by definition free of debris, cut an approximate 20cm strip and apply the adhesive side of the tape to the questioned surface. Be sure not to overload the tape to the point that all adhesive is used. Apply the strip to an inspected clear plastic sheet protector, and repeat until the trace evidence has been sufficiently collected. Be careful with the edges of the tape so as to prevent accidental debris collection. Once complete, the tape roll should be placed back inside the now open heat seal bag for re-inspection. See below for inspection guidelines. (a) Each lift should be sufficiently labeled. Notes should include the name and date of who had previously inspected the tape, where the lift came from, date and time of collection, how the tape lift was labeled, case number, etc. This method is not to be used for wet or oily surfaces. (b) Tape lifting will successfully lift gunpowder particles; however the nitrocellulose in the gunpowder residue will slowly dissolve in the adhesive of the tape. Therefore, the case agent should be advised to contact the Orange County Crime Lab for expeditious processing of the tape. (c) Tape that has not been inspected prior to use shall not be used for trace evidence collection. Inspection consists of viewing the tape roll under the microscope, removing all foreign debris and heat-sealing the tape in a clear plastic bag. The individual responsible for the inspection must place their initials, along with the date and time of inspection, in permanent ink on the exterior of the sealed bag. This inspection must take place between each use of the tape roll. 3. Scraping – Using a sanitized metal scoopula or wooden tongue depressor, scrape the questioned item over a large piece of paper. The paper must be large enough to

TRACE EVIDENCE

collect any evidence falling from the item being scraped. This can be a time consuming processing. 4. Collection of the Entire Item – At times it may be more effective to collect and package an entire object for direct lab analysis. Examples of this may include, but are not limited to, paint transfers on a pry object, glass embedded in a baseball bat, clothing, vehicle floor mats, etc. Special attention should be paid as to how the item is packaged, preventing loss of any evidentiary particles through the packaging. If the item is, for example, clothing, the corners of the paper bag should be taped.

6101.6 PACKAGING TRACE EVIDENCE Trace evidence may be packaged in paper bindles or folds. It may also be placed in a coin-sized envelope so long as all seams are sealed to prevent evidence loss. The bindle, fold, or coin-sized envelope shall then be placed in a larger evidence envelope for booking. Glass vials or plastic specimen containers may be used for mineral, soil and other dry botanical materials. Please note that this packaging is not suitable for wet or moist samples. All packages must be sealed at the closure in such a way as to prevent access. Placing red evidence tape at the closure and including the collector’s name and date of collection is one way to accomplish this. Take care not to break, crinkle or damage hairs by folding them into the bindles. Firmly attached trace evidence (i.e. glass shards embedded in a collectable object) should be documented and packaged intact with the item. Pieces of clear, inspected tape may be placed around the trace evidence to ensure that they stay in place. Easily lost trace evidence or evidence which is impractical to transport shall be documented and collected at the scene. If there exists the possibility of a physical match, the entire item and possible source shall both be collected, however shall not share a common packaging. The item(s) shall be properly documented with photographs (with and without scale) and notes prior to collection. Unknown or questioned samples shall never share a common package with known standards.

6101.7 SPECIFIC CIRCUMSTANCE TRACE EVIDENCE - LACHRYMATORS (TEAR GAS/ OC/MACE) Lachrymators are chemicals that are mucous membrane/skin irritants and are defined by California Penal Code 12401. They are frequently encountered in officer involved shooting cases. Clothing suspected of containing lachrymator residue shall be sealed in an airtight container immediately upon collection (i.e. unused one (1) gallon paint can).

6101.8 SPECIFIC CIRCUMSTANCE TRACE EVIDENCE - ADHESIVE TAPES The adhesive side of tape can provide trace, fingerprint and DNA evidence. Evidentiary adhesive tape should be fastened so that it will remain stationary, inside a gun box with the adhesive side up. Refer to Forensic Services Latent Print/Chemical Processing Manual for further information reference the analysis involved with processing adhesive tape.

TRACE EVIDENCE

6101.9 SPECIFIC CIRCUMSTANCE TRACE EVIDENCE - SOIL AND POLLEN Soil and pollen provide associative evidence. Put simply, soil and pollen collected from a crime scene can associate the suspect or victim to a particular geographical area. Similarly, soil found on a suspect or victim or his/her conveyance (i.e. vehicle, bicycle, plane, etc.) can associate them with a scene. Soil and pollen are class evidence and when an unknown or questioned sample is compared with a known or standard sample, the conclusion will be one of inclusion or exclusion and cannot be definitive. Soil, dirt, and dust are common elements at almost every crime scene and often contain copious spores and pollen. Soil can be collected from clothing, skin, hair, shoes, cars, carpeting, etc. Clothing, rugs, carpeting, blankets, any woven material, hair, and fur all provide excellent traps for pollen or spores. Among those, hair (whether human or animal) provides an excellent source for pollen and spore retrieval. For humans, this is due to the hair strands, along with the natural oils and various hair products, acting as a sticky filter trapping the spores and pollen as the wind blows through. Keep in mind that victim and suspect hair, as well as animal hair or fur, may be sampled for pollen and spore collection. Collection of soil or pollen evidence should be guided by logic and the circumstances of each case in particular. Incorrect collection can result in cross contamination and render the sample useless. Only a couple of tablespoons are necessary for soil collection. Always allow the soil to dry before sealing in a suitable glass, heat sealed, or evidence collection container. Clothing with dirt or soil on it should be allowed to dry and packaged in a paper bag, separating out each item of clothing. Implements or tools that have dirt or mud attached to them should be packaged in paper bags. Paper should be taped around any dried mud clumps to prevent loss of the evidentiary soil. Soil, dirt, or mud removed from vehicles (i.e. tire treads, wheel wells, etc.) should be collected systematically and each location of collection packaged separately with proper labeling. Soil or mud clumps should be collected in a manner that best maintains the integrity of the shape of the clump, with no crushing. Clumps should be packaged separately. For shallow grave soil collection, samples should be taken from the sides and bottom of the grave. In most instances an OCSD anthropologist should be summoned to assist with the scene. Samples taken from fields should be documented and collected in a grid pattern expanding outward from the questioned area. Continue collecting samples until a noticeable difference in soil color is noted. Soil collected from dwellings or commercial buildings should be collected near points of entry or exit, ingress or egress, or near shrubbery where a suspect could hide. Again, logic and case circumstance should guide collection.

6101.10 SPECIFIC CIRCUMSTANCE TRACE EVIDENCE - SUSPECTED ARSON At fire scenes, the fire or Arson Investigator should be the primary guiding force on which items are to be documented and collected as potential arson evidence, i.e. burned debris suspected of containing ignitable liquids, etc.

TRACE EVIDENCE

All items suspected of containing ignitable liquids must be promptly sealed within a Metal Friction Lid Can (MFLC) or a heat-sealed bag (i.e. items too large for the MFLC) as to best prevent the liquid from evaporating. Neither the bag nor the MFLC should be filled more than 2/3 full. Soil suspected to contain an ignitable fluid or accelerant should be placed in a MFLC, filling it no more than ½ way. The soil should be booked into the freezer. Dry clothing suspected of containing an ignitable fluid should be frozen. Wet clothing cannot be frozen and it is therefore necessary for the case agent to notify the Orange Crime Lab to expedite analysis as the progression of possible microbial activity on the clothing may alter the chemical signature of the ignitable liquid.

6101.11 SPECIFIC CIRCUMSTANCE TRACE EVIDENCE - GUN SHOT RESIDUE Gunshot residue may consist of the residue resulting from the combustion of the primer and powder, unburned primer or powder, and elements of the cartridge case and bullet. The Orange County Crime Lab no longer provides Gunshot Residue (GSR) kits or GSR kit processing. If GSR is requested, a GSR collection kit, purchased from an outside private lab, may be used and subsequently booked into Evidence. The collection of GSR may be completed on vehicles, live subjects, or deceased subjects with the prior approval of the Orange County Deputy Coroner Investigator and Orange County Crime Lab Criminalist, as soon as possible via the instructions included in the GSR collection kit.

6101.12 SPECIFIC CIRCUMSTANCE TRACE EVIDENCE - PAINT TRANSFERS Paint transfers are common in hit and run collisions, however may also be observed when implements are used to force entry into locations, etc. Questioned paint samples may be compared directly to a reference standard or may be evaluated for composition, which can aid in identifying the source of the transfer, i.e. the make and model of a vehicle. The clothing of a victim of hit and run should always be collected and packaged separately. Paint transfers from the suspect vehicle may be present within the clothes and may be the only source of information linking the victim to the car. Paint transfers that are present on vehicles or objects impractical to collect shall be collected down to the base of the material. All underlying layers of paint must be collected via a disposable or sanitized scalpel, scoopula, etc. For vehicles, these areas should be collected near the point of impact, but not at a position marred from the collision. Paint transfers present on implements or tools recovered at the crime scene should be collected as a whole item and packaged in a way that preserves the transfers or chips adhered to the surface.

6101.13 COLLECTION OF TRACE EVIDENCE STANDARDS The collection of evidentiary “questioned” trace evidence is often rendered useless without the collection and subsequent comparison to known standards. Most trace evidence by nature is “class” or associative evidence and can only result in an inclusive or exclusive conclusion. Therefore, the collection of reference standards is vital. Reference standards are also called exemplars.

TRACE EVIDENCE

Reference standards should never share a common package with questioned trace evidence. Reference standards shall be collected from areas surrounding, but outside the areas where the questioned evidence was collected. Reference standards shall be properly labeled as standards and the location of standard sampling shall be sufficiently documented. Trace evidence reference standards may include, but are not limited to, hair, fur, glass, paints, fibers, soil, physical objects, chemical solids and liquids, botanical vegetation, water controls, etc. 1. Head hair standards may be collected from victims, suspects, witnesses, etc. in the following manner. Exemplar head hairs should be collected with and without roots. (a) A total of 20-30 pulled hairs from the entire head must be collected, obtaining 4-6 from each region of the scalp (top, front, back including nape, and both sides). All plucked hairs may go into a single package (either paper bindle or completely sealed coin envelope) and sealed. The package shall be labeled and bear the initials of the individual collecting the samples, as well as the date and time of collection. Further, the package shall have the name of the individual from whom the reference standards were collected and a label that identifies the contents as “pulled head hairs. (b) You must collect a total of 60-80 cut hairs from the entire head, obtaining 12-16 hairs from each region of the scalp (top, front, back including nape, and both sides). Cut hairs should be cut two to three at a time and as close to the skin as possible. All cut hairs may go into a single package, (either paper bindle or completely sealed coin envelope) separate from that of the cut hairs, and sealed. The package shall be labeled and bear the initials of the individual collecting the samples, as well as the date and time of collection. Further, the package shall have the name of the individual from whom the reference standards were collected and a label that identifies the contents as “cut head hairs”. (c) The separate sealed packages of cut and pulled head hair can go in a single paper envelope and sealed as standard evidence. Hair reference standards do not need to be stored frozen (however evidentiary or questioned samples do. (d) The collection of evidentiary "suspect" trace evidence is often collected during sexual assault investigations. The collection of trace evidence from suspect(s) of sexual assault investigations shall be collected in accordance with the Orange County Crime Lab's protocol. 2. Pubic hair standards may be collected from individuals in the following manner. Exemplar pubic hairs should be collected with and without roots. (a) Wear gloves or have the subject pull the hair from various regions of the pubic area. For males, make sure hair is pulled from the scrotal region. Hairs should be pulled from different regions of the pubic area for a total of at least 15 pulled hairs with roots. All plucked hairs may go into a single package (either paper bindle or completely sealed coin envelope) and sealed. The package shall be labeled and bear the initials of the individual collecting the samples, as well as the date and time of collection. Further, the package shall have the name of the individual from whom the reference standards were collected and a label that identifies the contents as “pulled pubic hairs".

TRACE EVIDENCE

(b) Hairs should be cut from different regions of the pubic area, as close to the skin as possible, for a total of at least 35 cut hairs collected. All cut hairs may go into a single package, (either paper bindle or completely sealed coin envelope) separate from that of the cut hairs, and sealed. The package shall be labeled and bear the initials of the individual collecting the samples, as well as the date and time of collection. Further, the package shall have the name of the individual from whom the reference standards were collected and a label that identifies the contents as “cut pubic hairs". (c) The separate sealed packages of cut and pulled pubic hair can go in a single paper envelope and sealed as standard evidence. Further, the separate sealed packages of head and pubic hair can go into a single package for the same subject. 3. Fiber standards should be collected by cutting at minimum a 2” x 2” section of stationary rugs/carpets or items that are impractical to collect as a single or whole object. Although the same brand, different carpets may have been manufactured from different dye lots. Collection of fiber standards should be an accurate representation of these variations. (a) Vehicles may have different fibers on the interior door panels than on the floorboards or trunk compartment. Where applicable, floorboard mats should be collected. (b) Clothing, bedding, etc. should be collected in their entirety. Don’t forget about dryer lint catchers. Fiber standard collection should be a good representation of the variations within the scene or area. 4. Representative glass standards in the form of fragments and/or shards should be collected from each broken window, container, etc. If the case warrants it, a physical match comparison may be possible. Every effort should be made to collect the glass in a fashion that preserves its shape.