Journal of Criminal Law and Criminology Volume 31 Article 13 Issue 4 November-December

Winter 1940 Holes and Chemical Residues in Shooting Cases Joseph T. Walker

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Recommended Citation Joseph T. Walker, Bullet Holes and Chemical Residues in Shooting Cases, 31 Am. Inst. Crim. L. & Criminology 497 (1940-1941)

This Criminology is brought to you for free and open access by Northwestern University School of Law Scholarly Commons. It has been accepted for inclusion in Journal of Criminal Law and Criminology by an authorized editor of Northwestern University School of Law Scholarly Commons. BULLET HOLES AND CHEMICAL RESIDUES IN SHOOTING CASES Joseph T. Walkert Several new and important objec- value in reconstructing the circum- tives are introduced when the medico- stances surrounding the shooting and legal post-mortem examination of the in apprehending the responsible per- victim of a injury is under- son can hardly be over-estimated. taken. In ordinary practice an autopsy Observations bearing on the answers is performed to secure information of to questions proposed in the preceding medical or scientific interest. In medico- paragraph fall in three categories. legal practice it is performed primarily In the first category are the physical to determine, for legal purposes, the characteristics of the wounds. Excel- cause of death. Although both of these lent descriptions of wounds are to be objectives are important, many medical found in many of the more recent text- examiners and investigating officers are books on legal medicine (84) (85). unfamiliar with certain potentially rich These include descriptions and illustra- sources of information which are ex- tions of the differences between wounds tremely useful in the investigation of of exit and entrance; the characteris- the crime. To determine the cause of tics of the shot canal which indicate the death is, of course, fundamental. But direction of flight of the projectile; the to determine, insofar as possible, the evidences of explosive effects as are to circumstances surrounding the fatal be seen in contact shots; peculiarities acts is often more useful in the admin- of wounds attributable to the form and istration of justice. Among others, an- velocity of the bullet which produced swers to the following questions should them; peculiarities of wounds produced be sought. Was the wound produced by spent or bullets in . by a bullet? Could the injury have In the second category are the iden- been self-inflicted? From what direc- tifying features of bullets found in, or tion was the shot fired? How far was shell cases found near, the body. The the gun from the victim when the shot matching of bullets or shell cases for was fired? What kind of ammunition the identification or exclusion of ques- was used? What kind of was tioned weapons constitutes a highly used? specialized science which has been ade- The answer to these and other ques- quately presented by many authors tions may depend entirely upon the ex- (83). amination of the body and clothing of It is with the third category of ob- the victim. With the legal status of servations that this paper is principally evidence of this kind already estab- concerned. This has to do with the lished in the higher courts (27), its identification and interpretation of resi- dues of powder, lubricants, and metals t Massachusetts State Police, and Department of Legal Medicine, Harvard University. which may be found on the skin or [ 497 1 JOSEPH T. WALKER

clothing of the victim, or in the wound Bullet: The bullet from an automa- itself. It is necessary first to consider tic pistol generally consists briefly the components of the firearm of a core covered with a gilding and the cartridge in order to appreciate metal jacket (copper alloyed with 5 to the significance of these residues. 10% of zinc). This jacket may be bare or Firearm: For the purposes of this plated with , or, rarely in this coun- discussion only hand (revol- try, . A bullet of this type is vers and automatic pistols) will be in- designated as "full metal-jacket." In cluded. The barrel is generally made cartridges designed for revolvers the of or , rifled with from four to seven lands and grooves, twisting bullet is generally soft. It may be com- to either the right or left. Frequently posed of relatively pure lead, lead it is fouled from previous shots, plated with a thin layer of copper, or rusted, or oiled. Examination of the lead alloyed with , tin, or with interior will usually disclose the both antimony and tin. Spectrographic presence of metal fragments de- analysis of lead bullets shows the pres- rived from previous shots embedded ence of other elements in traces: cop- in the depressions of the gun bar- per, , silver and, occasionally, rel. This is particularly true near thallium (18) (75). Some revolver the breech where erosion of the barrel bullets have a copper or plated jacket is likely to be greatest (86) and where extending about halfway back from the surface of the bullet has been sub- the tip to the base. The soft metal of jected to the greatest stress at its cir- the core is exposed on the circumfer- cumference. Here the metal may often ence of the bullet near the base. In be seen to lie in strips at the edges of others, such as hollow point and soft the lands which impart the rotational point bullets, the jacket covers the base thrust to the bullet. Moreover, foul- and cylindrical portion, leaving soft ing from the powder charge and primer metal exposed at the tip. In all bullets, charge is frequently present and can be including jacketed bullets, the soft easily proved chemically. It is there- metal of the core is exposed at the fore possible that a bullet fired from base, or at the tip, or both. such a gun may carry with it traces of Lubrication: In general lead bullets any or all of the materials present on designed for revolvers are lubricated the interior of the -iron, by means of a semi-solid waxlike lubri- rust, oil and metals, as well as powder cant. Jacketed bullets designed for au- and primer fouling of previous shots. tomatic pistols are not so lubricated Cartridge Case: The cartridge case in (36). Spectrographic analyses con- most instances is of brass. Within re- ducted in this laboratory have shown cent years the primer cap at the base that the lubrication is generally con- of the cartridge has been nickel-plated. taminated with lead, either mechanic- Occasionally one also finds the brass ally or by the formation of lead com- case nickel-plated. pounds. BULLET HOLES AND CHEMICAL RESIDUES

Powder: Formerly the propellant compounds, including lead azide and charge in a cartridge was composed of lead styphnate; and potassium chlorate black powder. Since the introduction has been replaced by barium nitrate. of smokeless powder, black powder So where the residue of an old type charges have gradually disappeared, primer characteristically contains mer- until at present it is rare to find black cury and potassium, the residue of a powder cartridges. Black powder is modern primer characteristically con- a mixture of about 75% potassium ni- tains lead and barium. Antimony in trate, 15% sulfur and 10% charcoal. the form of stibnite is generally found Upon explosion it yields as solid resi- in both old and new primers. Zirconium dues mainly potassium sulfate, potas- metal is the latest element to be en- sium sulfide and potassium carbonate, countered. Recent analysis of the together with traces of the original primer residues of ninety-six makes components and nitrites, thiocyanates, and types of cartridges representing and thiosulfates (39) (68). both old and new ammunition with Smokeless powder is composed es- black and smokeless powder showed sentially of cellulose nitrate (single that the following elements were pres- base powder) or cellulose nitrate with ent in the percentage of residues in- nitroglycerine (double base powder) dicated. (68). The powder grains are generally Percentageof coated with graphite and are in the Element PrimerResidues form of disks or squares. Upon explo- Barium ...... 90% Antimony ...... 87% sion, smokeless powders leave very Lead ...... 75% little solid residue. That which is left Mercury ...... 67% consists of carbonized matter or graph- Potassium ...... 31% Tin ...... 9% ite in the form of a fine dust and un- Manganese ...... 4% burned or partially-burned grains of Zirconium ...... 1% powder, ranging in size from large Subsequent information received from visible particles to fine dust. Nitrites cartridge manufacturers indicates that and cellulose nitrate are the detectable tin compounds are not incorporated in chemical entities in this residue. primer mixtures, as the spectrographic Primer: Some years ago a typical analyses of the residues above would primer mixture contained mercury ful- imply. Primers leaving tin in the resi- minate, stibnite (native antimony sul- due of the explosion were therefore fide), potassium chlorate and powdered removed from the cartridges by the glass. Subsequently attempts were method of Chamot (82). In each in- made to eliminate mercury and to re- stance the primer compound was found duce the rust-producing properties of to be sealed into the cup with a small the residue of potassium chlorate. (26). disk of soft metal foil. The foil was This has resulted in the production of composed of a lead tin , weighing primers in which the mercury has been about 10 mg The disintegration of partially or entirely replaced by lead this foil upon firing doubtless gave rise JOSEPH T. WALKER

to the tin and a considerable portion of pected that the following substances the lead in the residues from these having origin in the gun barrel and primers. cartridge may on occasion be expelled To summarize, then, it may be ex- when the bullet is fired.

Substance Source

22,

M oo A4 V di

di ti 0w U P ct Pi2 M~W U1n. a. Rust, Iron ...... X Lead ...... XXX X XXX X X XXX Tin ...... X X XX Antimony ...... XX XXX XXX XX XX Mercury ...... X XXX Nickel ...... X X x Copper ...... X XXX XX Zinc ...... X XXX XX Barium ...... XX X XXX Potassium ...... XX XXX X XXX Carbon ...... XX XXX XX Nitrates ...... XX X XXX Nitrites ...... X X Sulfides ...... X XX ..... x XXX Sulfates ...... X xxx Carbonates ...... X Thiocyanates ...... X XX Thiosulfates ...... X XX Lubricating grease ...... XX Cellulose nitrate ...... XXX Note: XXX-Characteristically present. XX-Frequently present. X-Occasionally present.

The cross marks indicate the author's servers. It is largely upon the basis estimate of the frequency with which of the separate characterization of these the particular substance occurs in the patterns that valuable information can source mentioned. They have no exact be obtained. quantitative significance. In practice it is not to be expected Is the Hole a Bullet Hole? that these substances will be intimately This question is apt to arise in every mixed and form a homogeneous pat- shooting case. It is a particularly im- tern when fired from a weapon. Rather portant one when there are more holes it is to be expected that due to their in the clothing than can be accounted original differentiation, their various for by the number of shots believed to states of division and various , have been fired, or when the number they will tend to form separate and dis- of wounds in the victim is not in agree- tinct patterns. This has indeed been ment with the number of holes in the shown to be the case by numerous ob- clothing. BULLET HOLES AND CHEMICAL RESIDUES

The question is to be answered upon dirty or oily barrel than from a clean evidence of two general types: (a) the barrel (5) (71). If the shot is a close nature of the damage produced in the one, powder grains and particles of material under examination; and (b) wax lubrication may be seen adhering the presence or absence in it of traces to the fabric or skin. With very close characteristic of a bullet. Evidence of shots a dark smoke halo is present the first type is of a physical nature; around the hole. However, it is only that of the second type, chemical. under the most favorable circumstances The initial entrance of a bullet into that these deposits are readily detected fabric is generally circular or elliptical, with the naked eye. Dark fabrics, depending upon the angle of fire. If bloodstained and dirty, tend to obscure the bullet has been unbalanced in flight, this type of evidence. To obtain the it may strike with a wobble or end fullest information it is generally neces- over end; in either case, the hole is sary to resort to one or more of the likely to be irregular in form. The following useful methods: infrared size of the bullet hole is only roughly photography, radiography, spectrogra- characteristic of the caliber of the phy, or microchemistry. bullet. If the bullet has met the fabric Infrared Photography: It has been obliquely, the latter may be abraded pointed out by Schwarz and Boler (63), on the near edge to present an appear- Manczarski (40) (41), Elbel (11) and ance similar to that of moth-eaten area. Beil (2) that many of the products of This appearance is frequently encount- combustion of both black and smokeless ered in loosely-woven woolen garments powders are opaque to infrared light, or garments bearing a definite nap. and that by the use of infrared The exit of a bullet through clothing sensitive photographic plates and infra- is characteristically irregular in shape. red filters the dark contact ring and The bullet is generally traveling with smoke halo may be readily photo- much less velocity and frequently tip- graphed, even on dark or bloodstained ping end over end. Such an exit hole fabrics. The method is also applicable is not generally characterized by an to skin. The advantages of the use of abraded area. this procedure are more apparent in The most outstanding characteristic actual cases than experimentally, for of initial bullet entrances is the pres- its reliability is manifested under a ence of chemical substances wiped off great variety of disturbing conditions, the bullet during its passage through among the most frequently occurring the fabric or tissue in question. These of which is the presence of blood and substances compose a dark deposit dirt around the hole. Moreover, it is known as the contact ring around the no more difficult and scarcely more rim of the hole. On dark or blood- time-consuming than ordinary photog- stained garments it is not often visible raphy. The garment is in no way al- to the naked eye. The contact ring is tered and a permanent visual record is more intense with shots fired from a obtained. -JOSEPH T. WALKER

Radiography: As early as 1915, (18) (19), Bayle and Amy (1), Buhtz Demeter (8) employed X rays for the (7), Schwartzacher (64), Walker (75) detection of lead in the path of a bullet and Sanni6 (59) have used spectro- through tissue. Eidlin (10) and Man- graphic methods in detecting metals in czarski (40) have shown recently that the contact ring and smoke halo around by the use of soft X rays it is possible bullet holes. It has been shown that by to radiograph the metallic deposits in this means it is possible to detect lead fabric or tissue surrounding bullet and frequently other metals around the holes. Since these deposits are very entrance of a bullet into fabric. The thin, it is necessary to resort to rays spectrographic methods have the ad- of very low penetrating power. This vantage that they are sensitive and requires the effective use of potentials rapid. However, a portion of the fabric of 20,000 volts or less. The ordinary must be destroyed. X-ray tube, immersed in oil and with Microchemical methods: Lochte (35) a heavy window, will not emit rays at (36) (37) (38), Jansch and Meixner these low voltages. Consequently it (28), Briining and Schnetka (5), Hol- is necessary to use a specially designed sten (24) (25), Schmidt (60) and tube, such as the Grenz-ray tube of the Erhardt (12), and others also, have Westinghouse Company. At our sug- employed microchemical methods to gestion, Mr. H. F. Sherwood of the detect various metals around the bullet Eastman Kodak Company applied the hole. By these means lead, copper, stereo-Grenz ray technique, which he antimony, tin, mercury, nickel and zinc had previously successfully employed have been demonstrated. These meth- in the examination of fabrics and other ods, sensitive as they are, require con- thin objects (65) to this problem. His siderable technical skill, are frequently results have amply confirmed the work laborious, and suffer from the disad- of the earlier authors and have indi- vantage that they are not graphic. As cated that the stereo-technique will aid with the spectrographic method, a por- in characterizing the metal deposits. It tion of the fabric must be destroyed. has been shown that the contact ring is rich in metal if the bullet is a soft Has the Hole Been Caused by the one. This method, like the method of Entrance Or Exit of a Bullet? infrared photography, is simple and Clearly, the presence of a detectable does not destroy or alter the material powder residue pattern or a definite in evidence. It likewise produces a smoke halo or particles of bullet metal permanent pictorial record represent- or bullet lubricating waxes in a wide ing the spatial distribution of one class area surrounding the bullet hole is each of elements contributed by the bullet an indication that the hole in question to the object struck. Unfortunately, is an entrance. However, when the the equipment is not generally avail- shot has been fired at a distance this able. type of evidence is not present. The Spectrography: Gerlach and Gerlach only indications are to be found on the BULLET HOLES AND CHEMICAL RESIDUES

rim of the hole, where either the effects initial entrance of a bullet into clothing of the mechanical action of the bullet or tissue is a dark contact ring, made or the chemical traces left by the bullet by the physical contact of the bullet are evidence. (8) (10) (11) (40) (72). This ring As might be expected, the fibers at may not easily be observed on a dark the edge of the bullet hole are fre- or bloody fabric. Meixner (42), among quently pressed through the hole in the others, has emphasized that the con- direction of passage. This finding is tact ring at the entrance wound in skin not sufficiently constant, however, to may be simulated by a ring at the exit be considered with any degree of assur- having an entirely different origin. He ance. The explosive action of the believes the exit ring to be caused by bullet and gases in some instances the stretching of the skin beyond its causes a reversed appearance (73). elastic limit, coupled with subsequent Generally the clothing has been increased drying. Strassmann (72) handled before the expert has access and others (5) (10) (49) have shown to it, in which case any conclusions as that the darkness of the contact ring is to direction based on the direction of largely due to gun barrel oil and foul- the fibers must be regarded with great ing carried on the surface of the bullet: skepticism. More significant, however, a jacketed bullet fired from a clean is the occasional abrasion or moth-eaten barrel leaves very little residue around appearance of the fibers on the near the bullet hole. In confirmation of this, side. In tracing the path of the bullet it has been shown by Walker (75) that through the clothing and through the a bullet fired from a black powder tissues, materials dislodged by the cartridge through a clean gun barrel bullet near the entrance are deposited leaves very little potassium around the along the path in the direction of the bullet hole. However, subsequent bul- exit. Thus Strassmann (70) (71) (73) lets fired from smokeless powder car- emphasizes the fact that upon micro- tridges through the same gun barrel scopic examination fibers abraded from without intermediate cleaning leave the garments will generally be found abundant but decreasing amounts of in the tissue of the entrance wound in potassium. This experiment proves the body. No such fibers are to be that gun barrel fouling contributes a found in the exit wound, except where significant portion of the material of the shot canal is very short (43). the contact ring. The residues of prev- Fragments of bone and tissue will fre- ious discharges, lodged as fouling in the quently be found around the exit hole gun barrel, are swept out by the bullet, in clothing. However, this appearance transported on its surface, and de- sometimes occurs also in entrances posited on the first suitable object when the explosive action of the gases struck by it. or projectile causes a back-splashing of Lochte (36) and Demeter (8) were these substances (73). the first to show that the contact ring The most characteristic feature of the was in part composed of metals. In JOSEPH T. WALKER the case where a lead bullet was in- metals, two general methods have been volved, they proved the existence of used-microchemical and spectrograph- a heavy deposit of lead at the entrance, ic. Earlier atempts to detect hard with scattered fragments throughout jacket metals, such as copper, zinc, the entire shot canal and at the exit. nickel, by chemical methods in the con- Other authors (1) (7) (10) (12) (59) tact ring often failed (8) (37). Even (60) hive confirmed these results. As the detection of lead was not always Eidlin (10) points out, metals may orig- successful. Briining (5) has reviewed inally be derived from either (a) the more recent methods by which it the bullet, (b) gun barrel fouling, or is generally possible to detect lead and (c) the primer. To this may be added frequently the metals of jacketed bul- (d) powder (15) (75), and (e) car- lets. These methods, employing di- tridge case (12) (15). phenylthiocarbazone for lead and zinc Eidlin (10) finds that the metals of and rubianic acid for copper and nickel, the contact ring are largely derived are sensitive to a few micromilligrams from fouling of the barrel. Bullets of the metal sought. However, as fired from new and clean weapons fail Sanni6 (59) points out, cloth frequently to give a typical radiographically-de- contains considerable quantities of all tectable deposit of metals around the of these metals. The mere presence of bullet hole. Upon the basis of spectro- any of these metals around a bullet graphic analyses of contact rings from hole is without significance; it must be lead shots, Buhtz (7) concludes that there in appreciably greater quantities the lead present in the ring is derived than elsewhere to indicate a bullet en- from the particular bullet in only the trance. Even in the case of lead bul- smallest degree. From similar evi- lets, where the deposit of lead around dence, Walker (75) believes that the the entrance is often very great, care following factors are responsible, in de- must be exercised. Lead is often creasing importance: (1) the bullet; scattered throughout the shot canal, as (2) gun barrel fouling; (3) metallic Buhtz (7), Demeter (8) and Schmidt contamination of powder; (4) primer (60) have shown. Eidlin (10) feels residues. It is very.probable that the that the distribution of lead about the extent to which the metals from hole, not its quantity, is the most sig- the bullet or fouling are deposited on nificant criterion for the differentiation the object struck will depend on both of entrances from exits. Occasionally the hardness of the bullet metal and the a single flake at the exit may contain hardness and abrasive qualities of the more lead than the entire deposit at target. The X-ray method is most suit- the entrance. Furthermore, as Schmidt able for the graphic demonstration of (60) indicates, it is possible that a lead, but it generally fails to show a jacketed bullet might deposit very little deposit when jacketed bullets are used lead at the entrance, split while within, (10). and leave a heavy deposit at the exit. For the chemical demonstration of The chemical methods for detection BULLET HOLES AND CHEMICAL RESIDUES

of metals at the orifice, sensitive as they have the advantage that the exhibit is are, appear to lose much of their use- in no way altered. In critical cases the fulness if not supplemented by a graph- spectrographic method is satisfactory. ic method, such as radiography; and, Where it is necessary to search for only besides, as Sanni6 (59) states, the one of a few elements, microchemical methods require considerable skill, are methods are suitable. not quantitative, and do not leave a permanent visible result. From What Distmce Was the Weapon Although the spectrographic method Fired? first used by Bayle and Amy (1), and All methods for the deternination of subsequently employed by others, is distance are applicable to compara- superior to the microchemical methods tively short distances only. Under or- in several respects, it should be used dinary circumstances a bullet wound preferably in conjunction with radiog- may be self-inflicted only when the raphy as a topical (surface) control. weapon is held with the muzzle within Areas may be chosen that are repre- a few inches of the body. The deter- sentative; areas contaminated with mination of distance is therefore par- foreign matter may be discarded. ticularly valuable in this region. For- Where a choice must be made, pictorial tunately, fairly accurate determinations methods are preferable to purely are possible. All available methods de- qualitative or quantitative methods. pend upon the presence and distribu- Any quantitative method, other than tion of various ingredients of the one employing the entire area sur- muzzle blast. It is therefore necessary rounding the bullet hole, is unjustified to distinguish carefully between the unless one is able to show, by some contact ring produced in fabric or means, that the sample chosen is rep- tissue by the impact of the bullet and resentative of the entire area. The dis- the powder residue tattooing and tribution of metals around a bullet hole smoke halo produced by the muzzle is certainly not uniform. Milovanovie blast. The halo and tattooing are pres- (46) points out that atypical bullet ent only at short distances; the contact entrances are not uncommon. It there- ring is independent of distance. fore seems advisable that, before any There are five major types of mate- chemical or spectrographic method is rial emitted from the muzzle during undertaken, the bullet hole be radio- discharge of the bullet. These con- graphed to show the distribution of sist of (1) gases, (2) smoke (fine the metals being sought. dust, carbonaceous and metallic), (3) To summarize the methods of dis- residues of partially-burned and un- tinguishing entrance from exit holes by burned powder, (4) metal fragments or the presence or absence of traces, it droplets, and (5) wax or grease lubri- appears that the infrared and soft X cation. ray techniques are the most simple In order to visualize the process and the results the most graphic. They more readily and to evaluate the sig- JOSEPH T. WALKER nificance of each of the above factors, both black powder and smokeless pow- it is desirable to examine the course of der, contain carbon monoxide; the for- events within a revolver subsequent to mer to the extent of about 10% (68), the moment the firing pin strikes the the latter, 38% (44). Palteuf (51) and primer cap. The primer mixture ig- Meyer (44), as well as others (23) nites the powder, which under (57) (69), have shown that with con- pressure, progressively explodes. The tact or near-contact shots, where these bullet of lead alloy is forced out of the gases enter the body, carbon monoxide cartridge case into the barrel. In the hemoglobin is formed from the blood. case of a revolver it must pass through The shot canal becomes bright red. a space between the cylinder and the Spectroscopic proof of carbon monox- breech of the barrel. If the chamber is ide hemoglobin in the shot canal imperfectly aligned with the barrel a would thus serve as a proof of a con- portion of the lead of the bullet may tact or near-contact shot. be shaved off. In automatic pistols no Strassmann (70) reported a remark- such action can occur, for the barrel able case involving a putrified body, is a prolongation of the chamber. The which had remained immersed in barrel is provided with lands and water for several weeks. A bullet grooves which twist either to the right hole at one opening presented a or left. The bullet, being of a some- bright red appearance, in contrast with what greater diameter than that of the the corresponding orifice and the rest barrel, is compressed and elongated. of the body, which were greenish. In At the same time it receives an enor- a water extract of the tissue of the red mous rotational thrust. If the fit of the region, "carbon monoxide hemoglobin bullet is not perfect, gases may escape was clearly shown spectroscopically". past it and cause a preliminary dis- In view of the recent work of Schmidt charge before it emerges from the bar- (61) and others on the stability of car- rel (68). Subsequent to the emer- bon monoxide in putrified blood, it gence of a bullet further gases will seems more likely that the carbon be discharged. While this is in prog- monoxide, if present, would be in the ress, the muzzle is describing an up- form of carbon monoxide hemochromo- ward arc around the center of mass of gen, or a similar degradation product. the firearm. Thus, in general, matter Strassmann concluded that the hole was discharged before the bullet emerges caused by a bullet fired from short would be expected to reach the target range. No powder smoke or powder at a point below the bullet hole, and grains could be detected. anything discharged afterward, to Smoke: Both black and smokeless reach it above (24). Heavy particles powders give rise to a discharge in and dense particles might be expected which carbon and metals are present to carry a greater distance from the as a fine dust or soot. The smoke of a muzzle than light particles and gases. black powder discharge is much more Gases: The gases of combustion, of dense than that of a smokeless powder BULLET HOLES AND CHEMICAL RESIDUES

discharge. In either case, if the shot is turn of the slide to its forward position. fired from a comparatively short dis- This appearance, when present, not tance, the fine smoke will be deposited only serves to characterize a contact on the target around the bullet hole in shot, but in favorable cases may help to a roughly concentric manner. This de- identify the make of pistol. In some posit may take the form of a halo, cases similar appearances caused by showing a greater near its per- foreign particles in the powder or the iphery. The diameter and density of ejector rod of the cylinder of a re- the smoke halo serve as an indication volver may be encountered (57) (78). of the distance from which the weapon The chemical nature of the smoke was fired. In general, a definite smoke halo has been only partially investi- halo may be detected under most fav- gated. In the case of black powder, it orable conditions with smokeless pow- may be assumed to consist principally der at muzzle distances as great as of potassium salts and carbon, although twelve to eighteen inches, depending it is well known that it is generally on the type of weapon, the type of cart- contaminated with lead from the ac- ridge, and other factors. B. Miiller (48) companying lead bullets. Briining (4) believes that an estimate of distance has shown that in fresh residues much based on the intensity of blackening of this lead is in the form of sulfide; of the smoke halo is preferable to one in older residues, sulfate. based on its diameter. In actual prac- In the case of halos from smokeless tice it is difficult to measure this in- powder cartridges, more work has tensity. With dark and bloodstained been done. The halo proper does not garments infrared photography has necessarily contain nitrites or oxidizing proved useful (40) (63). Simonin (67) agents characteristic of unburned or and Brusatto (6) have pointed out that partially-burned grains of powder (35). with contact shots on skin covered A great portion of the dark material with several layers of fabric a modified consists of metals (5), the source of series of smoke halos or "cocarde" is which depends upon a great number of occasionally formed within the layers factors. of cloth. In this case the examination Many authors have pointed to the of the outer garment may reveal very strongly metallic nature of the smoke little in the way of a halo, whereas the halo. The earliest metal to be detected inner garments may show several con- was quite naturally lead. Lochte (36) centric rings. was able to dislodge lead particles from It should be noted here that when an the area surrounding the bullet hole automatic pistol is forcibly pressed up to a muzzle distance of Y to 1 m. against the skin at the moment of fir- in all cases where lead bullets were ing, a dark stamp mark of the outline employed. By polishing the dislodged of the forward end of the slide may be residues between glass slides or by the impressed around the bullet hole (16) use of X rays, Demeter (8) confirmed (78). The effect is caused by the re- the presence of particles of lead and JOSEPH T. WALKER found them to distances as great as ward above it. The droplets could be 12 m. Lochte felt that the lead was seen clearly, even, in some cases, with largely derived by the dislodging of the naked eye. Similar shots fired into the bullet from the cartridge case; woolen cloth left the wool fibers stip- Demeter, that it came from abrasion in pled with splashes of lead. The dis- the revolver barrel. Neither detected position of this lead was certainly not any lead in the bullet hole of shots fired concentric with the hole. As the dis- from automatic pistols. Demeter noted tance of the weapon from the target that the lead was frequently in the was increased to six inches, molten form of gray fluid droplets. Jansch splashes of lead were still detected, and Meixner (28) found lead to a dis- although less were to be observed. tance of 2 m. by methods similar to This lead appears to originate in the those of Lochte. particular bullet causing the hole. Mi- Eidlin (10) pointed to the fact that croscopic examination of the cylin- on the basis of X-ray evidence the lead drical surface of the fired bullet near around the bullet hole caused by lead the base at the following edge of each bullets fired at short range was in the land impression showed a molten ap- form of a ring, the diameter of which pearance and an apparent loss of mate- increased with distance. With increase rial. That lead bullets tend to melt in distance, the ring changed to an from the action of hot powder gases or inner and outer ring and, in general, friction within the barrel has long been became more punctate. known to those concerned with their Buhtz (7), employing a spectro- design. The presence of splashes of graphic method, found that the quan- molten lead around a bullet hole is, tity of lead immediately surrounding a among other things, an indication of a bullet hole from a lead bullet de- near shot. These droplets, in solid state, creased with the shot distance up to probably travel to considerable dis- 200 cm. By the analysis of the fabric tances. around the hole of near shots, he The presence of lead in the halo found the lead content more dense at around a bullet hole is not confined. to the center, less dense at the periphery. shots from lead bullets (5) (18) (24) In one experiment, Rankin (58) found (25) (59) (60) (75). At the base of that the lead content of the cloth of the jacketed bullets the lead core is ex- bullet hole decreased regularly up to posed to the action of hot gases. Many 100 feet. modern primers contain lead in the Recently the holes produced in lino- form of the azide, dinitrophenylazide, leum by lead bullets fired at close styphnate, thiocyanate, chromate, ni- range from a variety of revolvers were trate or dinitrobenzoate. The sealing examined microscopically in this lab- disk in the primer cup may be com- oratory. A large number of splashes posed of a lead-tin foil. It may be of molten lead was found immediately stated that in actual practice lead from surrounding the hole and extending up- one source or another is present in BULLET HOLES AND CHEMICAL RESIDUES

the muzzle blast of every type of car- reschi (17) was unable to dem- tridge fired in a used gun. Holsten onstrate mercury histologically beyond (24) (25) has made use of the general 3 to 4 cm. under similar conditions. presence of lead in modern primers to Buhtz (7) and Journi6, Piedelievre form the basis for the estimation of and Sanni6 (29) have tried the spec- distance based on the quantitative de- trographic method without satisfactory termination of this metal in concentric results, although Gerlach (18) claimed rings around the bullet hole. He em- that by employing the method of the ployed the sensitive diphenylthiocar- high frequency spark no difficulty was bazone method. Wickenhauser (80) encountered. criticized Hoisten's method as inappli- By a spectroscopic method Gerlach cable to oblique shots. B. Mfiller (48) (18) noted in several cases a prepon- states that the quantitative determina- derence of iron in the entrance wound. tion of lead for the estimation of dis- He was unable to establish definitely tance can be expected to be limited to its origin and differentiate it from exceptional cases. physiological iron. Fritz (15) showed Mercury in the form of the fulminate that this iron was in fact due to mate- is present in many primer caps, both rial carried on the surface of the bullet old and new. Upon detonation it re- or expelled with the powder. In the verts to metallic mercury. As early as smoke halo on the skin it was an indi- 1907 Georgii (20) observed droplets of cation of a close shot. Fritz used a his- metallic mercury in the residues of tological method employing potassium shots from Flobert revolvers up to a ferricyanide in 10% hydrochloric acid muzzle distance of 20 cm. The pro- as a reagent. pellent powder in cartridges designed Buhtz (7) was the first to point out for this firearm was composed largely that copper is to be found in the smoke of mercury fulminate at that time. halo of shots fired at short distances. Lochte, with Fiedler (37) and with By firing shots from cartridges pro- Danziger (38), was able to demon- vided with nickel-jacketed bullets, he strate mercury in the halo by chemical found copper in the smoke halo, but means when Flobert cartridges were not in the contact ring. He reasoned fired, but detected no mercury with from this that the copper was derived ordinary mercury fulminate primed from the cartridge case. Copper was cartridges. Schmidt (60), by a more found at distances up to 40 cm. by sensitive chemical procedure, detected spectrographic methods. Fritz (15) like- mercury in the later cases to a dis- wise detected copper histologically in tance as great as 25 cm. Piedelievre and the same manner as with iron. Mem- Simonin (53) and Journi4, Piedelievre branes of brown copper ferrocyanide and Sanni4 (29) have been able to were formed around each particle by show mercury droplets microscopically the potassium ferrocyanide reagent. up to a distance of 20 cm. with He found copper up to distances of 20 mercury - primed cartridges. Gau- cm. and concluded from an examina- JOSEPH T. WALKER

tion of the powder that the copper was an entirely erroneous result. Demeter derived from the case. Erhardt (12) (8) has shown that individual particles determined the copper quantitatively of bullet metal travel to considerable in the smoke halo in clothing of shots distances; in some instances, as great fired from automatic pistols. The cop- as 10 m. Obviously, then, one runs the per content decreased with distance up risk of an erroneous conclusion if he at- to 20 cm., where it reached the tempts to determine distance by quan- value for the cloth. titation in the smoke halo of a metal The determination of distance by the which is also a constituent of the bul- quantitation of metals around a bullet let. Thus the method of Holsten (24) hole is a process beset with many dif- (25) is applicable only to lead-primed ficulties. As early as 1915 Demeter jacketed bullets. (8) observed that the quantity of lead Clothing frequently contains lead, around the bullet entrance depends copper, zinc, tin and nickel (12) (19) upon the material of the bullet, the (25) (59) (80), in addition to other length of barrel, type of target, quality metals. If any of these metals is to be of barrel wall, construction of weapon, used for the purposes of quantitation, ratio of the caliber to the bullet diam- the tests must be suitably controlled, or eter, and form of the bullet, as well as a metal which is not commonly present the distance. And one may add many in fabric or skin should be chosen. A other less controllable factors, such as possible approach lies in the employ- the cleanness of the gun barrel, the ment of a metal commonly present in manner of firing the weapon (single the primer which is not present in the action or double action with re- bullet or cartridge. Barium is such a volvers), and the angle of fire. In addi- metal. It has the advantage of not tion there is the almost unsur- being frequently encountered in cloth- mountable difficulty of accurate and ing. In an experiment in this labora- representative quantitation without tory conducted to determine the dis- destruction of the entire bullet hole persion of the metallic constituents of and its surrounding area. The halo is bullet and primer around a bullet hole rarely, if ever, disposed symmetrically in cloth, a shot was fired at close range, around the hole in either form or quan- using a cartridge with a lead-antimony- tity. A preliminary discharge may barium primer and a lead bullet. A cause a heavy deposit below the bullet strip of cloth 3" wide and extending hole. An after-discharge creates a de- four inches on either side was cut posit above. The grooves may through the bullet hole. This strip was cause the formation of radiating areas placed on the flat surface of a 1,S" cop- of greater density in the pattern (55). per bar one-half inch by twelve inches. Flakes or chips of the metal in ques- The bar with adhering cloth was used tion, either from the bullet, cartridge as a moveable lower electrode against case or fouling in the gun barrel, may a stationary upper copper electrode in cause local accumulations that lead to the spectrograph. The copper bar was BULLET HOLES AND CHEMICAL RESIDUES

moved slowly through the spark while inches. The detection of these particles the plate-holder of the spectrograph was therefore becomes highly important, synchronously lowered. The resulting for their complete absence tends to spectrogram was a series of overlapping place the weapon outside of the suicide individual spectra, in effect a progres- range. There is one outstanding ex- sive analysis of a diameter of the smoke ception to this generalization, and that halo. It was noted that barium, as well occurs in the case of the absolute con- as lead and antimony, each increased in tact shbt (66). Here one may find no quantity toward the hole. This method traces of powder residue on the cloth- promises to be useful for experimental ing (54), a fact which might carelessly purposes. It necessitates destruction of be assumed to necessitate a more dis- a portion of the bullet hole. tant shot. Due consideration to the na- Lubrication: Particles of bullet lu- ture of the wound, the appearance of brication, present on the surface or in fabric at the bullet hole, and in partic- the cannelure of a bullet designed for a ular the infrared photographs of the revolver cartridge, may generally be smoke halo or stamp mark of the found around the entrance hole in muzzle will readily enable one to dis- shots at close range from revolvers. tinguish a contact from a distant shot. These particles are somewhat larger Highly characteristic of the contact than powder particles and tend to ad- shot is the cross-shaped tear of the here tenaciously to rough fabric. They fabric. A like appearance is found on may therefore occasionally be found on skin (68). cloth at a muzzle distance as great as In 1911 Wellenstein and Kober (77), nine feet. By means of a warm iron, advocated the use of a solution of Lochte (35) pressed tissue paper cov diphenylamine in strong sulfuric acid ered with blotting paper against the as a reagent for the characterization of garment. Lubrication stains produced powder residue particles. As is now well on the tissue paper were developed known the reagent is a general one, with Sudan III or with iodine or osmic responding to many oxidizing agents. acid vapors. Its response to powder residues, both Powder Residues: Whereas gases black and smokeless, is due to the and smoke have comparatively limited presence of nitrates and nitrites. The range, it has long been observed that production of the characteristic blue individual grains of powder, unburned color is due to a two-stage oxidation of or partially-burned, may travel to the diphenylamine; the first stage re- somewhat greater distances. Thus, if sulting in colorless diphenylbenzidine, a smokeless powder cartridge is fired the second in its blue quinoid deriva- into white cloth, a smoke halo may tive (60). generally be observed up to a distance Because of the corrosive nature of of twelve to eighteen inches, whereas the sulfuric acid in the diphenyla- powder grains are likely to be found mine reagent, the latter cannot be ap- as far as twenty-four to thirty-six plied directly to the skin or clothing. JOSEPH T. WALKER

Wellenstein and Kober (77) removed The latter was found to be the most the powder grains with a needle and satisfactory. The cloth was placed tested them on a porcelain plate. Va- against this material and beaten; the rious methods of brushing (22), beat- grains which adhered were individually ing (50) (72), scraping (66) or removed and tested. Kochel (33) swabbing (66) the subject to remove found the above method too laborious the powder grains have been proposed. and employed paper spread with water With but few exceptions, none of the glass. The diphenylamine reagent methods is sufficiently graphic to per- could be aplied directly to this sub- mit a reasonable estimate of distance. strate with a glass wool brush. Strassmann (72) spread that portion of The non-specificity of the diphenyla- the garment containing the bullet hole mine reagent is a source of great un- face down over a tin or wooden vessel certainty (10) (21) (22) (28) (35) within which rested a shallow glass (37) (57) (60). Oxidizing agents ca- dish lined with paraffin. The garment, pable of giving a blue color are com- held in place by means of an outer tin mon. Clothing very frequently contains hoop, was scraped or scratched. If the these substances (22) (48) (60). distance between the garment and the Therefore, with no satisfactory means paraffin surface is slight, the dislodged of applying the reagent to obtain powder grains will be found in an im- a true spatial representation of age of their original location on the the distribution of the grains around garment. They might then either be the orifice, great caution should examined microscopically, tested with be exercised in drawing any con- diphenylamine reagent, or both. Hil- clusions based upon the finding of schenz (22) covered the garment with a few scattered particles of a substance concentric rings of cardboard and which responds to the test. On the brushed out the fabric with a tooth other hand, the failure to find such par- brush, the process being carried out ticles does not entirely exclude their over a dish of diphenylamine reagent. presence. Infrared photographs show In this way, by successive removal of that the brush-out method of removal cardboard rings and rebrushing, the of powder grains is not complete. For numbers of particles at various dis- this reason Beil (2) believes that the tances from the bullet hole could be infrared photography of black powder ascertained. He found that it was dif- residues is superior to the method of ficult to free the grains from long- Hilschenz (22), particularly when the fibered fabrics. Dyrenfurth and Wei- bullet hole is dirty and when the gar- mann (9) tried various adhesive bases ment is deep-napped. with the intent of retaining the re- Foyatier (13) and others prefer bru- moved powder particles in their orig- cine in sulfuric acid to diphenylamine. inal relative positions. Cardboard was It is more specific for nitrates than spread with (a) glycerine gelatine, (b) diphenylamine (45). Simonin (66) para-rubber solution, or (c) "Mastisol". points out that it has a real advantage BULLET HOLES AND CHEMICAL RESIDUES when blue cloth is encountered, be- Ordinary glossy photographic paper cause of the fact that the test color is is completely desensitized by the usual red. Both the brucine and diphenyla- photographic hypo bath, washed thor- mine reagents suffer from the fact that oughly and dried. It is then immersed the colors are fugitive; no permanent in a warm 5% solution of "C" acid for visible record of the test can be pre- ten minutes. The treated paper is al- pared. The choice between the two re- lowed to dry. A pad of cotton cloth or agents appears to be largely a matter a towel is laid upon the table, on top of of individual preference. which a piece of the prepared paper is In 1928 Goroncy (21) proposed the placed face up. This must be of suffi- use of alpha naphthylamine and sulfan- cient size to accommodate all of the ilic acid in acetic acid, for the detection powder residue. On top of this, face of nitrites present in the residues of down, is laid the fabric containing the smokeless powder. A portion of the bullet hole. Next are placed a thin cloth is removed and extracted with layer of dry toweling, a thin layer of alcoholic potassium hydroxide. The toweling slightly moistened with 20% solution is acidified with acetic acid and acetic acid, and a final thin layer of dry the nitrites detected by the production toweling. The whole pack is then of a red color on the addition of the re- pressed with a warm electric iron for agent. The depth of color, under con- from five to ten minutes. trolled conditions, may be used as an The prepared photographic paper indication of the approximate distance when removed is found to have im- of the weapon from the garment. Con- pressed upon it a number of dark red trary to the diphenylamine test, the spots which correspond to the posi- Lunge reagent is specific for nitrites. tion of the partially-burned powder The test as conducted lacks specificity grains around the bullet hole. This test for powder residue. The individual is sensitive to black and smokeless grains are not represented spatially, powder residue, and is insensitive to all hence information as to distance is at other usual chemicals except nitrites. the most vague and uncertain. Fur- The test is specific for nitrites and thermore, a portion of the fabric must highly indicative of powder residue if be destroyed. consideration is given to the spatial dis- Walker (74) has proposed a method tribution of the particles around the of spatially representing powder resi- bullet hole. A permanent graphic rep- due patterns on fabric by printing the resentation of the powder residue pat- pattern against gelatinized paper treat- tern is produced, without in any way ed with "C" acid (2-naphthylamine-4, destroying or significantly altering the 8-disulfonic acid). Alpha-naphthyla- fabric of the bullet hole. Blood stains mine and sulfanilic acid or "H" acid (1- do not react nor greatly interfere. amino-8-naphthol-3, 6-disulfonic acid) There is a general agreement be- may be used in the same manner. Fol- tween authors that in actual cases no lowing is a description of this method: estimate of distance should be made JOSEPH T. WALKER without firing a series of test shots from a grazing has taken place the greatest the same firearm, with the same type of strain is produced on the entrance side ammunition and against the same type of the wound. This last conclusion is in of target (32) (33) as were believed to agreement with the X-ray results of have been involved in the questioned Eidlin (10), who found a heavier de- shot. Great variation exists between posit of metals in the contusion ring at the various types and calibers of fire- the near side of the hole. Furthermore, arms, as well as between the makes with near shots an elliptical form to the and types of cartridges. F. MiUller (49) outer metal ring made visible by X-ray found that the variations in mechanical photography is a means of estimating operation of revolvers greatly affected the direction. Elbel (11) points out the character of the powder pattern. that the smoke halo made visible by Employing a revolver of unknown infrared photography is also useful for make, the cylinder of which fitted so this purpose. Likewise the C-acid poorly that every time the weapon was print test of Walker may be used. In fired part of the bullet was shaved off, each case where the evidence is ob- Miiller found the powder pattern very tained the heaviest deposit is to be ex- irregular. Scarcely any estimate of dis- pected on the near side of the bullet tance could be made. hole. Considerable caution should be Karhan (30) has investigated the ef- exercised, however, for other uncon- fect of burial and submersion in water trollable factors may give rise to a false on near-shot characteristics. He finds appearance of an angle shot. In esti- that even under the most adverse con- mating direction, due consideration ditions some traces, either chemical or should be given to the fact that the microscopic, are likely to be found. clothing is generally free to swing and Kraft (34) found that a handker- assume positions other than that of the chief held over the muzzle did not ap- surface of the body. preciably alter the powder residue pat- Wilson (81) has shown in an actual tern. shooting case that a particular revolver regularly left a denser deposit of black From What Angle Was the Shot Fired? powder residue directly above the bul- Any method of graphic representa- let hole. He attributed this phenome- tion of the residues surrounding a bul- non to a premature escape of the gases let hole is capable of being used as a at the top portion of the barrel, due to means for approximating the angle of faulty manufacture. Although in this incidence of the path of the bullet to particular case this explanation might the struck surface. Piedelievre (52) hold, it is a recognized fact that even has shown that the more inclined the with well-constructed revolvers the de- angle of incidence, the longer the posit is more dense above the bullet wound or abrasion. A shot cannot hole. This is attributed to the discharge enter human skin at an incidence angle of gases subsequent to the emergence of 50 to 100 or less. Moreover, where of the bullet. In revolvers the muzzle BULLET HOLES AND CHEMICAL RESIDUES describes an upward arc while the bul- cient exact information of these factors let and gases are being discharged; con- will be available frequently in actual sequently the after-discharge is located cases. above the bullet hole (55) (83). In automatic pistols the center of mass What Type of Powder Was Used? lies near the axis of the barrel. As a In the United States only three types result there is little tendency for the of powder need to be considered- muzzle to rotate upward, and the after- black, smokeless and semi-smokeless. discharge is likely to be found on the A black powder discharge is character- target concentric with the bullet hole. ized by a heavy black deposit, inter- Whatever the cause, the regular pro- spersed with dense black or gray par- duction of a dense eccentric deposit ticles, or minute spherical sulfur-col. serves as a means of orienting the posi- ored masses. Infrared photographs of tion of the weapon with respect to the the pattern will disclQse a typical pic- target. In this laboratory it has been ture of dense black spots (2). Chem- found that the droplets of molten bul- ical analysis of one of these spots for let-metal likewise are to be found on nitrates, potassium, sulfate and sulfides the target above the bullet hole. In definitely indicates black powder resi- some cases they range slightly to the dues (25) (31) (37) (39) (56) (68). left; in others, to the right. The sulfides which are present in fresh black powder residues are rapidly con- Caliber of the Bullet verted into thiosulfates and sulfates. It is particularly difficult to estimate Potassium sulfide is lost after four to the caliber of the bullet from a mere six hours (45). Black lead sulfide (4) examination of the hole produced by it from the lead of the bullet and iron in an elastic material, such as fabric or sulfide (45) are converted after several skin tissue. Holsten (24) (25) states days into light-colored sulfates. These that the caliber can be estimated in and other changes form a basis for the near shots by determining the diameter estimation of time elapsed since a wea- of the chemically-provable lead-con- pon was fired (39) (45). A modifica- taining smoke halo, where lead primer tion of the C-acid print test can also be charges have been used. Buhtz (7) be- employed if the residue is fresh. In- lieves that the quantity of spectro- corporation of lead acetate on the gela- graphically-detectable lead in the con- tinized paper will give a pattern of tusion ring is dependent upon distance semi-metallic spots of lead sulfide. and caliber; if one can be determined, Smokeless powder residues do not the other can be estimated. That the give a dense black pattern of individual dispersion of the smoke halo elements spots when photographed with infra- and powder residues is dependent upon red light. Neither does the residue con- the caliber to a certain extent is obvi- tain appreciable quantities of potas- ous, but the other factors involved are sium, sulfates or sulfides. Black pow- very numerous. It is doubtful if suffi- der residues are alkaline to litmus; JOSEPH T. WALKER smokeless powder residues are acid (4) erties of the muzzle blast from a black (5) (35) (55) or neutral (26) (39). powder cartridge is its intense heat. The acidity of the residue grains is Weimann (76), in a series of experi- probably dependent upon the internal ments, showed that singeing generally pressure during explosion; high bar- occurred to distances of 20-30 cm. and rel pressures tend to produce a non- sometimes to Y m. Tissue and body acid smokeless powder residue. Nippe hairs are singed or scorched, and cloth- (50) suggests that the distinction be- ing is frequently ignited. In contrast tween black and smokeles powder resi- smokeless powder causes no singeing dues can be confirmed by the fact that or burning (10 (14) (22) (35) (44) the nitrates of the former are soluble (57) or at most negligible traces at a in water. Black powder charges are distance of a few centimeters (23) only occasionally encountered today. (76). They are never met with in ammuni- It is possible in some instances to tion designed for the automatic pistol. distinguish the various types of smoke- We may expect a lead bullet and a bul- less powder. If the combustion has been let lubricant where black powder is so incomplete as to leave large particles, encountered. As has been shown else- their form may be recognized (31) where (75), the presence of black pow- (68). In bulk, double base powder may der residue in the contact ring proper, be distinguished from single base by to its exclusion elsewhere, does not warming at 1000 C. in a shallow dish necessitate a black powder charge for covered by a watch glass. The nitrogly- the particular bullet in question. It cerine vaporizes and condenses as a fog implies a previous black powder charge on the watch glass where it may be fired from the same weapon. tested with diphenyamine reagent. A Semi-smokeless powder consists of modification of this method has been an intimate mixture of the principal found useful in this laboratory. A frac- components of both black and smoke- tion of a flake of powder or a small less powders. The proportion is gener- particle of residue is placed in a capil- ally 80% black and 20% smokeless. The lary tube, one end of which is sealed. grains of the original powder are dull- The tube is evacuated (water pump), black, angular particles resembling sealed, and placed in a copper heating black powder, except for the lack of block provided with a thermometer. A luster and more angular appearance. portion of the tube is allowed to pro- When fired they leave a residue similar ject from the block. The block is to black powder residue in appearance heated to 1000 C. If the powder is and chemical composition. It is doubt- double base, nitroglycerine distills into ful if a distinction could be made be- the cool portion of the tube. It may be tween the two residues in actual cases, observed under a microscope or tested unless unburned grains happen to be for by breaking the capillary under present. diphenylamine reagent. It has also One of the most characteristic prop- been observed that certain smokeless BULLET HOLES AND CHEMICAL RESIDUES

powders tend to leave very plastic resi- As has been indicated previously, the dues. In tests conducted on linoleum source of the deposit left on the con- with automatic pistols (no lubrication), tact ring is to a large extent dependent splashes of powder residue similar to upon thie abrasive qualities of the tar- the splashes of molten lead were ob- get. Soft fabric or skin tissue may served. When the shots were fired into merely wipe the loosely-bound fouling cloth, the powder residue particles sur- from the surface of the bullet; bone or rounded the fibers and assumed the abrasive fabrics may remove the bullet contour of the surface. So far this metal. Much will depend upon the cir- phenomenon has been encountered cumstances. only when double base powders have It is of course obvious that radiogra- been used. phy of the bullet hole will be helpful. Eidlin found no detectable deposit on What Type of Bullet Caused the Hole? the contact ring in clothing when jack- Many attempts have been made to eted bullets were fired at a distance. determine the composition of the bul- If black powder can be proved, a lead let from the metals present in the halo bullet is implied. Proof of an auto- or contact ring. Schwarzacher (64) matic pistol necessitates a jacketed bul- analysed fragments of metal found in let. the vicinity of the bullet hole, while Bayle and Amy (1), Brining (4), Ger- Was the Wound Self-Inflicted? lach (18) (19) and Sanni6 (59) have Suicide with a firearm held in the analysed the contact ring with this hand necessitates a muzzle distance of purpose in mind. The assumption must twenty-four inches or less. Powder of course be made that the metal de- residues, and frequently metals, lubri- posits are derived from the surface cation and components of a smoke halo, metal of the particular bullet which are detectable within this distance. Ab- made the hole. That this is not true sence of near-shot traces tends to ex- in the majority of cases has been shown clude suicide. In shots found to have by numerous investigators. Thus. lead been fired within two feet, due consid- around a bullet hole is often derived eration must be given to the location from gun barrel fouling or primer resi- of the entrance and the anatomical pos- dues (7) (24) (25) (60) (75). Cop- sibilities. per and zinc can as easily be derived It has long been known that powder from fragments of cartridge case metal residues escape around the breech of a as from the bullet jacket (7) (12) (15). poorly-constructed revolver and are to Antimony and tin are constituents of be observed occasionally on the hand primers as well as of bullet metal (60) of a person who has recently fired the (75). Even nickel around a bullet hole gun (21) (22) (23) (43) (66). In does not necessarily signify a nickel- 1922 Benitez (3) recommended the jacketed bullet, for the primer caps of application of the diphenylamine re- modern cartridges are nickel-plated. agent to the interior of a paraffin mold JOSEPH T. WALKER

of the surface of the right hand as a tissue back on the firing hand. Par- means of detecting powder residue par- ticles of bone may be expelled with ticles. B. Mueller (47) recently con- such force as to cause small puncture ducted experiments on the presence of wounds (78). powder residues on the hand of the person firing the gun. He came to the Examination of Clothing: Proposed conclusion previously reached also by Procedure others (22) (43) that a number of re- In order to employ as many useful volvers give no residue, and that a neg- methods as possible in a single pro- ative result on the hands of the victim cedure for the examination of a bullet does not exclude suicide. The occur- hole in clothing, the following sequence rence of powder residues is largely de- is proposed: pendent on the precision with which 1. Visual Examination. Note size the revolver is constructed. Mueller and shape of hole, disposition of fibers did not use the paraffin mold-diphenyla- at entrance, evidence of abrasion, evi- mine method of Benitez (3). dence of residues. It should be mentioned at this time 2. Photography. The use of panchro- that if it is necessary to exercise cau- matic film is recommended for the rep- tion in drawing conclusions based on resentation of the appearance of the the appearance of a few particles of a garment at the hole. substance which responds to the 3. Infrared Photography. Use infra- diphenylamine test on the clothing red sensitive plate and Eastman # 88 A around the bullet hole it becomes even filter to represent smoke halo, black more important to do so when evalu- powder residue and contact ring. ating residues on the hand. Here at 4. Radiography. Use soft X rays to most the number is not great, and the visualize deposits of heavy metals in human hand is even more liable to be smoke halo and in contact ring. contaminated with foreign substances 5. Microscopic Examination. Use bin- than clothing. Matches and tobacco, ocular dissecting microscope to exam- among other common things, give a ine fabric, to locate foreign fibers, positive diphenylamine test. tissue or bone fragments in hole, and to Werkgartner (79) mentions the fact find powder particles. Evidence of that blisters and pinch marks are to be splashes of molten lead may be seen. found on the firing hand on occasion, 6. Remove questioned traces for after the use of automatic pistols. testing. Distinguish black from smoke- Holding the weapon in the right hand less powder. Remove particles of metal and supporting it with the left hand located by radiograph. frequently leaves blood or powder 7. Press area around hole with tissue stains on the left hand. In addition the paper under a mildly-warm iron. Lo- explosive action of the gases during a cate lubrication traces. contact shot may blow fragments of 8. Perform C-acid print test for pow- BULLET HOLES AND CHEMICAL RESIDUES der residue. Add lead acetate to paper 8. Cleaning. Wash away the adher- if there is a question of fresh black ing blood. Re-examine the skin for evi- powder. dence of tattooing. 9. Spectrographic analysis of suitable BIBLIOGRAPHY portion of halo or contact ring as shown 1. Bayle and Amy, "Sur un perfectionne- by infrared photograph, and radio- ment apportN a la technique de 'analyse graph, or- spectrale," Ann. de Med. leg. 8: 525 (1928). 2. Beil, "Die Infrarot-Photographie," Arch. f. 10. Microchemical analysis, as an al- Kriminol. 100: 179 (1937). ternate or supplement to spectro- 3. Benitez, "Agunas consideraciones sobre las manchas producidas par los disparos graphic analysis, might indicate muzzle de armas de fuego," Rev. de Med. leg. de Cuba 1: 30 (1922); Abstract in Ann. de distance or type of bullet. Med. leg. 3: 303 (1923). 4. Brfining, "Beitrlige zur Untersuchung und Beurteilung von Geschossen, Waffen und Examination of Wound: Proposed Einschiissen," Archiv. f. Kriminol. 77: 81 Procedure (1925). 5. Briining and Schnetka, 'qJber die chem- 1. Visual Examination. Note size isehe Untersuchung and die Beurteilung von Einschiissen," Archiv. f. Kriminol. 101: and shape of bullet hole. 81 (1937). 2. Photography. General-view pho- 6. Brusatto, "Sulla disposizione a 'ccoccarda' degli aloni di affumicatura negli strati pro- tographs of body as well as individual fundi degli indumenti," Arch. di Antrop. wounds. Pan- crimin. 55: 896 (1935); Abstract, Deut. Zeit. close-up views of the f. d. ges. ger. Med. 27: Ref. 39 (1937). chromatic film is recommended. 7. Buhtz, "Metallspuren in Einschusswun- den," Deut. Zeit. f. d. ges. ger. Med. 18: 3. Infrared Photography. Use infra- 609 (1932). red sensitive plates and an Eastman 8. Demeter, "Uber den Nachweis des Bleies in Schusswunden," Vierteljahrschrift f. #88A filter, to represent the smoke ger. Med., usw. 50: 174 (1915). halo, stamp mark or contact ring. 9. Dyrenfurth and Weimann, "Uber Nach- weis and Fixierung von Nahschuss spuren," 4. Removal of Tissue. Remove the Deut. Zeit. f. d. ges. ger. Med. 11: 288 (1928). skin surrounding the bullet hole. 10. Eidlin, "Roentgenographischer Nachweis des Metallringes am Einschuss," Deut. Stretch it on a board with tacks or Zeit. f. d. ges. ger. Med. 22: 204 (1933). pins. Remove portions of the bullet 11. Elbel, "Experimentelle Untersuchung Uiber den Schmutzsaum bei Schussverletzungen," tract and place them in separate small Deut. Zeit. f. d. ges. ger. Med. 28: 359 (1937). bottles or jars, unfixed. 12. Erhardt, "Der Kupfernachweis im Schuss- feld und seine Bedeutung fir die Schuss- 5. Radiography. Trim away subcu- entfernungsbestimmung," Deut. Zeit f. d. ges. ger. Med. 30: 234 (1938). taneous tissue and place on cellophane. 13. Foyatier, "Atude sur les r~actions de com- Use soft X rays to visualize the metals. poss nitris des poudres," Ann. de Med. leg. 4: 521 (1924). 6. Microscopic Examination. Exam- 14. Fraenckel, "Uber Nahschusserscheinungen, ine the skin and bullet tract under a insbesondere der Browning-pistole," Vier- teljahrschrift f. ger. Med., usw., 43: dissecting microscope. Remove ques- (suppl. H. 2) 154 (1912). tioned metals, fibers or other particles 15. Fritz, "Der mikroscopische Nachweis von Esen und Kupfer an Einschusswanden im for testing. Schnitt und andere wertfolle Befunde an Schnitten von Schusswunden," Deut. Zeit. 7. Chemical Analysis. Cut out small f. d. ges. ger. Med. 23: 289 (1934). portions of tissue for spectographic or 16. Garsche, "Die Stanzmarke, en Zeichen des absoluten Nahschusses," Archiv. f. Krim- microchemical analysis. inol. 97: 120 (1935). JOSEPH T. WALKER

17. Gaureschi, "Der Nachweis des Quecksil- 36. Lochte, "Uber den Nachweis der Fett- bers be! Schussverletzungen," Deut. Zeit. und Bleispur bei Kleiderschussverletzun- f.d. ges. ger. Med. 23: 89 (1934). gen," Ibid, 45: (suppl. H. I.) 133 (1913). 18. Gerlach, "Spectralanalytische Untersuch- 37. Lochte and Fiedler, "Ergebnisse der chem- ungen von Schusskaniilen und Geschossen," ischen Analyse von Schussspuren," Ibid. Deut. Zeit. f. d. ges. ger. Med. 22: 438 (1933). 47: 68 (1914). 19. Gerlach and Gerlach, Clinical and Patho- 38. Lochte and Danziger, "Weitere Ergebnisse logical Applications of Spectrum Analysis der chemischen Analyse von Schuss- 86-93 (1934). spuren," Ibid. 49: 7 (1915). 20. Georgii, "Uber die Gerichthrztliche Bedeu- 39. Lucas, Forensic Chemistry and Scientific tung der Flobertschusswunden," Viertel- Criminal Investigation (1935) 199-216. jahrschrift f. ger. Med., usw. 33: (suppl. H.) 253 (1907). 40. Manczarski, "Uber die Anwendung der Infrarotphotographie zur Unterscheidung 21. Goroncy, "Der Nachweis von Nitriten bei des Ein- und Ausschusses bei Fernschiis- der forensischen Beurteilung der Schuss- sen," Deut. Zeit. f. d. ges. ger. Med. 28: verletzungen," Deut. Zeit. f. d. ges. ger. 366 (1937). Med. 11: 482 (1928). 41. Manczarski and Neuman, "The Use of In- 22. Hilschenz, "Zur Frage der Entfernungs- frared Photography for the Purpose of Es- bei bestimmung Schiissen mit rauchschwa- tablishing Near Shot Characteristics on chem Pulver, und i/ber die Technik des Clothing," (Polish) Czas. sad.-lek. 3: 189 Nachweises des Pulverresten," Deut. Zeit. (1936); Abstract, Deut. Zeit. f. d. ges. ger. f. d. ges. ger. Med. 14: 234 (1930). Med. 27: Ref. 379 (1937). 23. Hofmann-Haberda, Lehrbuch der gericht- liche Medizin (Elfte Aufl., 1927) Pp. 318-356. 42. Meixner, 'qrrefiihrende Befunde an Auss- chfissen," Deut. Zeit. f. d. ges. ger. Med. 24. Holsten, "Zur Frage der Schussentfer- 1: 151 (1922). nungsbestimmung bei Verwendung von Sinoxidmunition," Deut. Zeit. f. d. ges. ger. 43. Meixner, "Schussverletzungen durch Hand- Med. 26: 389 (1936). feuerwaffen," Archiv. F. Kriminologie 75: 81 (1923). 25. - , "Untersuchung iUber die Nach- weismethoden und fiber die Verteilung des 44. Meyer, "Die Kriterien des Nahschusses bei Bleis im Schussfeld," Ibid, 28: 205 (1937). Verwendung rauchschwacher Pulver," Vier- teljahrschrift 26. Huff, "The Cause and Prevention of After- f. ger. Med., usw. 35: 22 (1908). Corrosion on the Bores of Firearms," Ind. 45. Mezger and Heess, "Die Bestimmung des Eng. Chem. 12: 862 (1920). Zielpunktes, wann eine Waffe das letztemal 27. Inbau, "Scientific Evidence in Criminal beschossen und eine Patrone verfeuert Cases," J. Criminal L. and Crim. 24: 843 wurde," Arch. f. Kriminol. 87: 239 (1930). (1933). 46. Milovanovie, "Zur Beurteilung von Schuss- 28. Jansch and Meixner, "Nahschussspuren an verletzungen," Arch. f. Kriminol. 102: 176 Kleidersticken," Beitrge zur ger. Med. (1938). 3: 82 (1919). 47. Mueller, B., "Untersuchungen fiber die 29. Journi6, Piedelievre and Sanni6, "La pro- Befunde an der Schusshand nach Abgabe jection de mercure par les coups de feu," von Schiissen mit Trommelrevolvern," Ann. de Med. leg. 13: 303 (1933). Deut. Zeit. f. d. ges. ger. Med. 27: 149 (1937). 30. Karhan, "Uber die Verhalten von Nabs- chussspuren von Nitro- und Schwarzpulver 48. MUller, B., "Macht die Einfiihrung der auf Kleidungsstiicken gegenilber atissern Sinoxid-Munition eine Anderung, unserer Einflissen," Deut. Zeit. f. d. ges. ger. Med. Methodik zur Entfernungsbestimmung von 21: 202 (1933). Schiissen notwendig?", Deut. Zeit. f. d. 31. , "Lasst sich nach einem Schuss ges. ger. Med. 28: 197 (1937). aus dem Pulverresten die Art des Pulvers 49. Miiller, F., "Bestimmung der Schussentfer- microscopisch feststellen," Deut. Zeit. f. d. nung bei Faustfeuerwaffen und Sinoxid- ges. ger. Med. 21: 451 (1933). munition," Arch. f. Kriminol. 104: 142 32. Kipper, "Neue Ergebnisse bei mit Nitro- (1939). munition angestellten Schiessversuchen," 50. Nippe, "Wesen und Wert der Deut. Zeit. f. d. ges. ger. Med. 5: 192 (1925). Diphenyla- minschwefelsiureprobe zum Nachweis von 33. Kochel, "Kriminaltechnisch Neues zur Schiesspulverspuren," Deut. Zeit. f. d. ges. Frage des Nahschusses," Deut. Zeit. f. d. ger. Med. 2: 641 (1923). ges. ger. Med. 24: 55 (1935). 34. Kraft, 'Der Verlauf der Geschossbahn in 51. Palteuf, "Uber die Einwirkung von Pulver- der Kleidern," Archiv. f. Kriminol. 87: 64 gasen auf das Blut und einen neuen Befund (1930). beim Nahschusse," Wien. klin. Wochenschr. 35. Lochte, "Beitrag zur forensischen Beur- 3: 989, 1015 (1890). teilung von Kleiderschussverletzungen," 52. Piedelievre, D6robert and Charton, "Aspect Vierteljahrschrift f. ger. Med., usw. 43: des orifices d'entrde des balles selon 1'angle (suppl. H.) 170 (1912). du tir," Ann. de Med. leg. 16: 607 (1936). BULLET HOLES AND CHEMICAL RESIDUES

53. Piedelievre and Simonin, "Contribution a 69. Strassmann, F., Lehrbuch der gerichtliche l'etude mddicoldgale des crasses qui se Medizin (1895). forment dans le canon des armes a feu," 70. Strassmann, G., "Versuche zur Unterschei- Ann. de Med. leg. 9: 549 (1929). dung von Einschuss und Ausschuss," Arch. Deut. Zeit. f. d. ges. ger. Med. 17: 237 f. Kriminol. 71: 308 (1919). (1931). , Unterscheidung von 54. Ponce, 71. "Zur 'Estimation of the Distance from Ein- und Ausschuss," Klin. Wochenschrift which a Revolver was fired," Archivos 2: 1695 (1923). Med. leg. 7: 215 (1937). (Spanish) Abstract in Deut. Zeit, f. d. ges. ger. Med. 29! Ref. 597 72. - , "Jber Kleiderschiisse," Beitr. (1938). z. ger. Med. 6: 114 (1924). 55. Popp, "Uber kriminalwissenschaftliche 73. , "Schwierigkeiten bei der Beobachtungen aus der Schusstechnik," Beurteilung von Schussverletzungen," Ibid. Vierteljahrschrift f. ger. Med., usw., 47: 8: 149 (1928). (suppl. H. I) 188 (1914). 74. Walker, "Chemistry and Legal Medicine," 56. Porta, "Uber den Wert des Schwefelnach- New Eng. J. Med. 216: 1024 (1937); or in weis zur Erkennung von Schwarzpulver," Smith and Glaister, Appendix 67. 57. Puppe, in Lochte's Gerichtsdrztliche Tech- 75. , in Harrison's Proceedings nik (1914). of the Sixth Summer Conference on Spec- 58. Rankin, in Harrison's Proceedings of the troscopj and Its Application (1939) 1-7. Sixth Summer Conference on Spectroscopy 76. Weimann, 'Die Flammanwirkung bei Waffen and Its Application (1939) 6-9. mit Rauchstarker Munition," Arch. f. Krim- 59. Sanni6, "L'identiflcation par analyse spec- inol. 89: 191 (1931). trographique des orifices de projectiles sur 77. Wellenstein and Kober, "Uber den Nach- les v6tement," Ann. de Med. leg. 19: 91 weis von Pulvereinsprengungn bei Ver- (1939). wendung moderner Handfeuerwaffen mit 60. Schmidt, "Beitrag zur chemischen Analyse rauchlosem Pulver," Zeit. Unters. Nahr- von Schussverletzungen," Deut. Zeit. f. d. ungsmittel 21: 544 (1911). ges. ger. Med. 18: 353 (1932). 78. Werkgartner, "Eigenartige Hautverletzun- 61. Schmidt, "Untersuchungen Uiber Kohlen- gen durch Schiisse aus angesetzten Selbst- oxyd-Hilmochromogene," Deut. Zeit. f. d. ladenpistolen," Beitr, z. ger. Med. 6: 148 ges. ger. Med. 27: 102 (1937). (1924). 62. Schwarz, "Zum Nachweis von Pulverriick- 79. Werkgartner, "Schirfungs- und Stanzver- standen an der Schiesshand," Arch. f. letzung der Haut am Einschuss durch die Kriminol. 91: 159 (1932). Miindung der Waffe," Deut. Zeit. f. d. 63. Schwarz and Boller, "Eine neue Methode, ges. ger. Med. 11: 154 (1928). urn Schmauchspuren auf dunkelen Unter- 80. Wickenhauser, "Uber die M6glichkeiten lagen Sichtbar zu machen," Arch. f. Krimi- eines quantitativen und qualitativen Blei- nol. 96: 229 (1935). nachweises im Schussfeld bei Verwendung 64. Schwarzacher, "Spectrographische Unter- von Sinoxidmunition," Deut. Zeit. f. d. suchungen von Geschossen der Faustfeuer- ges. ger. Med. 31: 298 (1939). waffen," Deut. Zeit. f. d. ges. ger. Med. 13: 81. Wilson, "Observations In a Case Involving 226 (1929). Powder Patterns and the Fallibility of Eye- 65. Sherwood, "Stereoscopic Radiography of Witnesses," J. Criminal L. and Crim. 26: Cloth," Rayon Textile Monthly (August, 601 (1935). 1937). 82. Chamot, Microscopy of Small Arms Primers 66. Simonin, "Ttude pratique de l'identification (1922). des tatouages et du diagnostic du suicide 83. Hatcher, Textbook of Firearms Investiga- par le r~actif a la diph6nylamine," Ann. tion, Identification and Evidence (1935). de Med. leg. 9: 552 (1929). 84. Logarde, Gunshol Injuries (1916). 67. Simonin, "Traces laiss~es dans les vite- 85. Gonzales, Vance, Helpern, Legal Medicine ments par les coups de feu tir~s de pros: and Toxicology (1917). tatouage en cocarde," Ann. de Med. leg. 86. Sveshnikoff, 8: 261 (1928). "Some Factors Affecting the Life of Machine-Gun Barrels," U. S. Bureau 68. Smith and Glaister, Recent Advances in of Standards Technologic Papers No. 191 Forensic Medicine (1939). (1921).