Improved method for shooting distance estimation. Part 1. Bullet holes in clothing items

An improved method for firing distance estimation on clothing is described. The novel part of the method includes transfer of total nitrite (nitrite ions and smokeless powder residues) from the target to an adhesive lifter. After the transfer, lead and copper deposits around the bullet entrance hole are visualized by rhodizonate and rubeanic acid, respectively. The Modified Greiss Test is carried out after alkaline hydrolysis of the smokeless powder residues on the adhesive lifter.     

Image analysis as an adjunct to sodium rhodizonate test in the evaluation of gunshot residues: an experimental study

It is important to investigate the clothing, as well as the body, to determine the range of fire of entry wounds in firearm injuries. Clothing can affect the amount of gunshot residues (GSR) reaching the body and their distribution. The amount and distribution of the GSR also vary according to the distance between the firearm and the target. Sodium rhodizonate test provides valuable data when clothing is available for examination. In the absence of clothing, light microscopic examinations may add additional information regarding the range of fire. In this study, a sodium rhodizonate test was done on 80 garment samples containing the bullet entrance. The 80 calfskin samples were processed histologically and were stained using Alizarin Red S. These were also evaluated with computer-assisted image analysis. Gross residues were seen on military camouflage clothing in samples from < or = 45-cm group. White flannel undershirts under the military camouflage contained rhodizonate-positive particles only around the contact wounds. With image analysis, however, the residues could be detected also in the skin samples of the 2.5-cm- and 5-cm-range groups. We suggest that the image analysis can be combined with other techniques and it can provide valuable data in the determination of entry wounds and also in the estimation of firing distance.     

Identification of gunshot residues in fabric targets using sector field inductively coupled plasma mass spectrometry technique and ternary graphs

During criminal investigations involving firearms, the detection of gunshot residues (GSRs) is one of the most important evidences. In the present study, a new method to identify trace evidences of GSRs, deposited around the bullet entrance hole, in different types of fabrics used as targets, is described. The experiments were carried out using a 0.38-inch caliber revolver, and 9-mm and 0.40-inch caliber pistols. Testimonies of 2.25 cm(2) of the fabrics were cut around the bullet entrance and digested with 10% nitric acid. Antimony, barium, and lead were analyzed in the remaining solution using a sector field inductively coupled plasma mass spectrometer. The concentrations of the elements were detected at levels up to few microgram per square centimeter. The use of ternary graphics allowed us to identify specific patterns of distribution for blank samples and the clear distinction between the revolver and pistols used.     

92式手枪射击距离与射击残留物分布密度相关性的研究

目的研究92式手枪射击距离与射击残留物分布密度的相关性,为射击距离的推断提供依据。方法选择92式手枪,在带皮的猪肉上覆盖白色棉布,设计了0m,0．1m,0．2m,0．5m,1．0m,1．5m,3．0m,5．0m,10m,15．0m,20．0m,25．0m共12个距离进行射击,提取白棉布上的弹孔圆周和距弹孔2cm的圆周上的射击残留物,利用扫描电镜／能谱仪对不同射击距离遗留在白棉布上的射击残留物进行检验。结果白棉布上射击残留物分布密度与射击距离呈负相关的关系。结论根据棉布上射击残留物的分布密度,能够推断射击距离,对涉枪案件中射击距离的判断有一定的参考价值。     

Improved method for shooting distance determination. Part 2--bullet holes in objects that cannot be processed in the laboratory

An improved method for firing distance determination on exhibits that cannot be processed in the laboratory such as cars, doors, windows, or furniture is described. The novel part of the method includes transfer of total nitrite (nitrite ions and smokeless powder residues) from the target to an adhesive lifter. After the transfer, vaporous lead and copper deposits around the bullet entrance hole are visualized on the target by sodium rhodizonate and rubeanic acid, respectively. The Modified Griess Test is carried out after alkaline hydrolysis of the smokeless powder residues on the adhesive lifter.     

The influence of a possible contamination of the victim's clothing by gunpowder residue on the estimation of shooting distance

A study was conducted to assess the influence of a possible contamination of the victim's clothing by gunpowder residue on the estimation of shooting distance. The study was focused on the scenario in which the contamination might be caused by the surface on which the shot victim could fall. Contamination of two types of textile was examined after contact with two types of surfaces. One round was fired above those surfaces (the line of firing parallel to the surface) prior to the contact. It was found that few gunpowder residue particles could be transferred to the clothing. These findings should be taken into account when interpreting results for shooting distance estimation in cases when a minute quantity of gunpowder residue particles is found around the bullet entrance hole.     

Machine washing or brushing of clothing and its influence on shooting distance estimation.

Experiments were conducted to assess the effect of machine washing or brushing of clothing items on Gunshot Residue (GSR) patterns (gunpowder residues, lead, and copper, deposits) around bullet entrance holes. Results show that those treatments decrease considerably the amount and density of GSR. However, for close shooting distances not all of the GSR deposits are removed. Remaining patterns may be visualized by specific color reactions and used for shooting distance estimation.     

Postmortem Computed Tomography and Magnetic Resonance Imaging of Gunshot Wounds to the Neck

Postmortem magnetic resonance imaging (MRI) is rarely used for the radiologic assessment of gunshot injuries, although it has clear advantages over postmortem computed tomography (CT) with regard to the imaging of soft tissue injuries. Another benefit in using MRI is that lodged projectiles composed of nonferromagnetic material such as lead present only marginal metal artifacts compared with severe artifacts on CT. This case report presents CT and MRI findings in a case with two gunshot wounds to the neck: a perforating wound and a nonperforating wound with a lead bullet lodged in the cervical spine. The decedent underwent CT and MRI before the scheduled autopsy. A ring of radiopaque material under the dermis in the fatty tissue was identified at both entrance wounds on CT, which was indicative of contact shots. The perforating gunshot was clearly indicated on CT by bullet fragments along the wound channel through the perforated 6th cervical vertebra and the fractured cricoid cartilage at the exit wound. The second trajectory, however, was only assumed based on the presence of gunshot residues at the entrance wound and the position of the lodged bullet. The radiologic assessment was severely impeded by the metal artifacts on CT. Barely noticeable metal artifacts on MRI allowed for clear visualization of the soft tissue injuries and the ruptured medulla oblongata. Only MRI clarified the soft tissue injuries of the brainstem noninvasively, which could provide specific and graphic information on the rapidity of death and the incapacitation of the victim.     

Radiodense bullet wipe around osseous entrance gunshot wounds

“Bullet wipe” is the material deposited by a bullet on any surface with which it comes into contact after it is fired and may contain debris from the gun barrel, including particles of primer and metal fragments from previously fired bullets. X‐ray analysis is a non‐destructive method by which traces of metallic elements can be visually detected. The analysis of osseous defects for radiodense bullet wipe (RBW) assists in determining the presence or absence of perforating gunshot wounds, especially in fragmented, skeletonized remains. The aim of our current study was to determine the frequency of RBW around entrance firearms injuries that perforated bone. We prospectively analyzed entrance gunshot wounds for RBW over a three‐year period using digital X‐ray analysis (n = 59). We retrospectively reviewed the corresponding autopsy reports to determine the frequency of RBW by biologic sex, reported ancestry, age‐at‐death, location of wound, manner of death, range of fire, bullet caliber, and presence of bullet jacket. Data were analyzed by Fisher's exact test or Chi‐square test with significance levels accepted at p < 0.05. RBW was present in 66% (n = 39) of examined cases. Decedent characteristics did not significantly alter RBW distribution, including biologic sex (p = 0.75), reported ancestry (p = 0.49), and age‐at‐death (p = 0.43). Additionally, the location of the osseous entrance gunshot wound, manner of death, range of fire, and cartridge caliber did not affect RBW detection. All cases involving non‐jacketed rounds (n = 5) showed RBW (p = 0.30). To our knowledge, this study is the first to report the frequency of RBW detection from osseous entrance gunshot wounds.     

Firing distance estimation through the analysis of the gunshot residue deposit pattern around the bullet entrance hole by inductively coupled plasma-mass spectrometry: an experimental study

The use of inductively coupled plasma-mass spectrometry (ICP-MS) in the study of gunshot residues (GSR) is relatively recent, and only a few studies have been published on the subject. In the present paper, this instrumental technique has been used to study the deposit pattern of the GSR around the bullet entrance hole, through the analysis of antimony (Sb), barium (Ba), and lead (Pb). The data obtained were used to establish a mathematical model for estimating the firing distance. Test shots using a 6.35-mm pistol were made against a target of cotton tissue, and the amounts of Sb, Ba, and Pb deposited in quadrangular pieces of the target, cut from 4 radial positions, were determined by ICP-MS. In these experimental conditions, it was possible to estimate the firing distance on the interval [20-80] cm. The best linear correlation between ln m and d, where m is the mass of Sb, Ba, or Pb in the samples, expressed in mug/g of target tissue, and d the firing distance, was obtained at radial distances between 3.5 cm and 4.5 cm from the entrance hole. The best regression curve which adjusted to the data was a linear multiple regression between the firing distance and the logarithm of the mass of each element: d = a + b(1)X(1) + b(2)X(2) + b(3)X(3), where X(1) = ln m (Sb), X(2) = ln m(Ba) and X(3) = ln m (Pb). The accuracy of firing distance estimation using only 1 or 2 elements was not significantly different from the one obtained with the 3 elements.     

Confusing injury findings in a suicidal gunshot fired to the chest from a carbine with a sawed-off barrel

The stellate bullet entrance wound is one of the facultative features of a contact shot. For the formation of a star-shaped wound two factors are of special importance: first, an extensive bony support underlying the skin in the entrance region, and second, a strong propellant charge of the cartridge fired. Contact shots to the precordial region usually do not cause stellate entrance wounds, even if high-powered rifle ammunition is used. In the reported case, an injury pattern was observed that was not in line with normal findings and seemed confusing at first. Following a suicidal gunshot to the chest from a sawed-off carbine 98a (cal. 8 x 57 Js), a 4.5 cm wide, gaping bullet entrance wound with radiating tears was found. Instead of the usual pocket, the anterior thoracic wall showed a fist-sized area of destruction with extensive undermining of the subcutis. Not far from the entrance hole, a rib fragment had become displaced retrogradely thus perforating the skin from the inside out. The unusual pattern of findings could be explained by the fact that the barrel had been sawed off: as a result of this manipulation, a considerable part of the propellant charge had been converted outside the barrel, i.e. in the initial section of the bullet path.     

Analysis of primer residue from lead free ammunition by X-ray microfluorescence

In forensic science, the analysis of gunshot residues was traditionally done by the detection of lead (Pb), antimony (Sb) and barium (Ba) usually found in a primer. However, the recent development of lead-free ammunition represents a new challenge for ballistic specialists. This analysis study gunshot residues from primers and ammunitions in the area surrounding bullet holes, a very important tool to determine the shooting distance. The ammunitions used were 9 mm Luger and .38 spl + p calibers, where lead in the primer was replaced with strontium (Sr) and where the lead bullet was plated with copper (Total Metal Jacket). Gunshot analysis results were obtained using an energy dispersive X-ray microfluorescence spectrometer. The method allows the detection and quantification of strontium residues on the target up to a distance of 45 cm.     

Suicidal gunshot to the nape from a small-bore rifle

A 55-year-old man was found dead on the bed lying on his side in a pool of blood with a bullet entrance hole in the nape. Behind his body, a semi-automatic rifle Remington Nylon, cal. .22 LR, was detected. As the gunshot entrance site was rather unusual for suicide, a forensic autopsy was performed, which showed a contact shot to the nape with the bullet path running upward to the left frontal area. The man had been treated with citalopram for delusional depression, so that a suicidal act seemed plausible, and the autopsy and criminalistic findings were also compatible with this assumption. A remarkable fact of the present case is that a long firearm had been used. Reports on suicidal shots to the nape are comparatively rare in the medicolegal literature and usually refer to pistols or revolvers.     

Comparison of GSR Composition Occurring at Different Locations Around the Firing Position

Abstract: Variations in gunshot residue (GSR) compositions are used in the reconstruction of shooting incidents. In this study, GSR samples taken from seven different locations around and in the firearm were collected and analyzed using scanning electron microscopy/energy dispersive X‐ray analysis. Four different types of ammunition were applied. Very low correlations were found when different ammunition were used. This clearly shows that it is possible to differentiate between ammunition types. When the same ammunition was used, high correlations were found between samples taken from external positions (such as hands of shooter, bullet‐entrance holes) but poor correlation was found between internal samples (such as firearm barrel, cartridge case) and external samples. A high degree of association was found between samples that simulated victim and shooter. These findings clearly demonstrate that GSR comparison studies are meaningful but care needs to be taken when choosing suitable exhibits. External samples (such as hands of shooter, bullet‐entrance holes) are more suitable candidates than internal samples (barrel of the firearm, cartridge case).     

Gunshot injuries as a topic of medicolegal research in the German-speaking countries from the beginning of the 20th century up to the present time

The 100th anniversary of the foundation of the German Society of Legal Medicine is a good opportunity to review its contributions to forensic wound ballistics. The present article gives an overview of the scientific development in this field with special emphasis on work pioneering new developments and findings valid up to the present day, for example the presence of carboxyhemoglobin in the vicinity of the entrance wound as a sign of a contact or close-range shot [A. Paltauf, Wien. Klin. Wochenschr. 3 (1890) 984-991, 1015-1017]; the correct interpretation of the muzzle imprint [A. Werkgartner, Beitr. Gerichtl. Med. 6 (1924) 148-161] and the retrograde ballooning of the bullet entrance region in contact shots [F. Hausbrandt, Dtsch. Z. ges. Gerichtl. Med. 38 (1944) 45-76; H. Elbel, Med. Welt 20 (1958) 343-345]; wound patterns from captive-bolt livestock stunners [H. Czursiedel, Dtsch. Z. ges. Gerichtl. Med. 28 (1937) 132-133]; singeing of synthetic fiber textiles in close-range shots with nitro powder ammunition [S. Berg, Arch. Kriminol. 124 (1959) 5-8,17-22]; the wound ballistic processes on penetration of the bullet and the origin of the abrasion collar [K. Sellier, Beitr. Gerichtl. Med. 25 (1969) 265-270]. More recently medicolegal research in the German-speaking countries covered the following subjects: studies of the dynamic bullet-target interactions in experimental gunshots to simulants and composite body models; use of modern imaging techniques (CT, MRI) in the pre-autopsy diagnosis of lethal gunshot injuries; injuries from blank guns; mechanisms of incapacitation by gunshot injuries; development of improved methods for the evidence of gunshot residues on the firing hand; backspatter from close-range shots; medicolegal contributions in the discrimination of accidental, homicidal and suicidal gunshot injuries.     

Medicolegal aspects of witnessed suicide due to gunshot to the head. II. Legal medicine aspects and examination of the firing hand

The second part of the paper on suicides by gunshots to the head in the presence of witnesses focuses on relevant morphological autopsy findings such as entrance site, signs of close range or contact shots, bullet path etc. and also discusses selected aspects of ascertaining gunshot residues. For the identification of the shooter an integral medicolegal assessment of all the facts including the investigation results and the autopsy findings is essential. However, the morphological findings alone do not allow safe diagnosis, as for example in a homicide the temporal region, which was affected in all our cases, may have been deliberately chosen by the perpetrator as a localization typical of suicide. Thus methods to ascertain gunshot residues on the firing hand (by means of adhesive films and the polyvinyl-alcohol collection method--PVAL) are of great practical importance. In seven cases adhesive films and/or the polyvinyl-alcohol collection method were used. In one case the gunshot residues (GSR) were analysed by means of tape lifts and subsequent scanning electron microscopy (SEM). It was found that especially the combined application of topographical (adhesive tape/PVAL) and cumulative (SEM) methods allowed for the doubtless identification of the shooter, thus usually confirming the suicide. By the example of one case it is demonstrated that without the immediate collection of evidence at the scene objective reconstruction of the event becomes impossible. On the basis of the reported cases recommendations are finally given for a differentiated approach in the medicolegal evaluation of alleged witnessed suicide by gunshot (to the head).     

Suicidal single gunshot injury to the head: differences in site of entrance wound and direction of the bullet path between right- and left-handed--an autopsy study

The aim of this study was to determine the differences in the anatomical site of a gunshot entrance wound and the direction of the bullet path between right- and left-handed subjects who committed a suicide by a single gunshot injury to the head. The retrospective autopsy study was performed for a 10-year period, and it included selected cases of single suicidal gunshot head injury, committed by handguns. We considered only contact or near-contact wounds. The sample included 479 deceased, with average age 47.1 ± 19.1 years (range, 12-89 years): 432 males and 47 females, with 317 right-handed, 25 left-handed, and 137 subjects with unknown dominant hand. In our observed sample, most cases involved the right temple as the site of entrance gunshot wound (about 67%), followed by the mouth (16%), forehead (7%), left temple (6%), submental (2%), and parietal region (1%). The left temple, right temple, and forehead were the sites of the gunshot entrance wounds, which were the best predictors of the handedness of the deceased (Spearman ρ = 0.149, P = 0.006). Our study showed that the direction of the bullet intracranial path in cases of suicide was even a more potent predictor of the handedness of the deceased (Spearman ρ = 0.263, P = 0.000; Wald = 149.503, P = 0.000).     

A case of external beveling with an entrance gunshot wound to the skull made by a small caliber rifle bullet.

The external beveling caused by an entrance gunshot wound to the skull has not been completely explained, but the mechanism is probably a combination of several factors including the angle of shot, twisting force of a rotating bullet, blow-back effect, velocity, shape and size of the bullet, outspread of the kinetic energy from the bullet, and resistance of the skull.     

Concordance Rate for the Identification of Distant Entrance Gunshot Wounds of the Back by Experienced Forensic Pathologists Examining Only Images of Autopsies

The images of 66 gunshot entrance wounds with a defect on the back, a bullet in the body, hemorrhage along the wound track, and logical certainty that it was an entrance wound were collected from the files of a moderately busy medical examiner's office. Participants numbering 22 board‐certified forensic pathologists viewed a single digital archival image of each of the 66 entrance wounds randomly mixed with 74 presumptive exit wounds to determine whether they were entrance or exit wounds. The concordance rate for correctly identifying the 66 logically known entrance wounds was 82.8% with a range from 58% to 97%. This pilot study was conducted to provide an evidence‐based approach to the interpretation of the direction of gunshot wounds by reviewing pathologists with access only to archival photographs, and it is not a measure of the accuracy to distinguish entrance from exit wounds when given all of the circumstances.