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.     

A novel method for the analysis of discharged smokeless powder residues

A novel method for the estimation of intermediate-long firing distance range is proposed. The method is based on the characterization and chemical analysis of the smokeless powder particles on the target. An adhesive lifter is applied to collect the suspected gunshot residues (GSRs) from the surface of an object, and a Modified Griess Test (MGT) is carried out after alkaline hydrolysis on the adhesive lifter. Visualized particles are removed from the adhesive lifter under a microscope. Two systems are used for the analysis of organic discharge residues from the smokeless powder: (1) gas chromatography/thermal energy analysis (GC/TEA) for the analysis of nitroglycerine (NG) and 2,4-dinitrotoluene (2,4-DNT), (2) gas chromatography/mass spectrometry (GC/MS) for the identification of organic components such as DNT, NG, and some stabilizers. By using this procedure and confirming that the suspected particles are indeed GSR, one can estimate the intermediate-long firing distance of c. 0.75-3 m in the presence of very few particles and provide information for the classification of ammunition type in casework.     

Improved method for shooting distance estimation. Part III. Bullet holes in cadavers

An improved method to estimate firing distance on human body surfaces is described. The novel part of the method includes a chemical test in addition to the traditional visual and microscopic examinations of the gunshot wounds. This chemical test consists of a transfer of the gunpowder residues from the area of a gunshot wound to an adhesive lifter; the residues are then visualized as total nitrite after alkaline hydrolysis by the Modified Griess Test (MGT). When cadavers are in an advanced stage of decomposition or when gunshot wounds are in hairy areas, the information obtained by this chemical test can be crucial for shooting distance evaluation. In other cases it may improve the accuracy of the examination. In some cases, the results obtained by this test may assist in the discrimination between entrance and exit gunshot wounds.     

A possible source of reference DNA from archived treated adhesive lifters

During the course of a double murder trial, it became apparent that the two adhesive lifters from the two cadavers had been mislabeled before being presented in court. The question was raised whether DNA testing from the biological material remaining attached to the lifters could resolve this mix-up. In fatal shooting cases where a bullet has been fired through a body surface, an adhesive lifter is applied directly to the entrance wound. The total nitrite residues, as well as biological material surrounding the wound (blood, hair, tissue) are transferred to the adhesive lifter. The nitrite residues are used for estimating firing distance. In a worst-case scenario, the biological material on the lifter may be the only remaining reference material from a victim. In this paper, we examined whether the biological material retrieved from adhesive lifters could be used for DNA typing after the lifters had been treated for GSR pattern. In as much as the biological material found on the lifters can be typed and profiled following physical and chemical treatment, we submit that archived adhesive lifters can be used as a future source of reference DNA from cadavers where no other sample is available.     

Removing interfering contaminations from gelatin lifters

Gelatin lifter is widely used for recovering shoeprints from crime scenes. Dusty shoeprints removed from paper with loose fibers, cloth or plasterboard, might be concealed by the detached fibers. A novel technique to clean the gelatin lifter from the interfering contaminations, using adhesive lifters, was developed. The adhesive lifter is applied directly on the surface of the gelatin lifter, and is removed instantly. The adhesive lifter removes the upper layer of the attached material on the gelatin lifter. After removing the concealing material from the hidden imprint, the quality of the visualized imprint is improved. The cleaning process can be applied as many times as needed and the optimum number is different for each substrate. The small dust particles comprising the shoeprint remained attached to the sticky side of the gelatin lifter even though the adhesion force applied by the adhesive lifter is great. Repeating the procedure too many times could harm the quality of the print severely, yet the advantages of this method are greater than the risks of relocation of image quality reduction.     

Lifting techniques for finger marks on human skin previous enhancement by Swedish Black powder — A preliminary study

An examination was done to investigate whether certain lifting techniques can lift recovered latent fingerprints on human skin surfaces of living subjects. For recovery Swedish Soot powder mixture (Swedish Black) was used.Donors intentionally placed fingerprints on the skin surface of living subjects. Finger marks were then in all cases recovered with Swedish Black powder. The procedure was repeated after 1 h and 4 h. Treated finger marks were secured and preserved as latent fingerprint evidence by different lifting processes. Having examined skin surfaces and finger marks we observed that the lifters such as white instant lifter, white fingerprint gelatin, black fingerprint gelatin, silicone, transparent adhesive tape, are suitable. Moreover, white fingerprint gelatin and white instant lifter proved to be very good at lifting treated finger marks. Black fingerprint gelatin was very good also, but finger marks were examined by slant light.     

Comparing the additive composition of smokeless gunpowder and its handgun-fired residues

Detecting the use of handguns via the determination of the organic additives in smokeless gunpowder residues (OGSR) presents a promising alternative to primer metal residue analysis. Compositional analysis of the gunpowder additives nitroglycerin, diphenylamine, and ethyl centralite provides information that can associate residue samples with unfired gunpowder. We evaluated the composition of seven reloading smokeless gunpowders, both in bulk and as single particles, by ultrasonic solvent extraction/capillary electrophoresis. Handgun-fired residues obtained from three common weapon calibers loaded with the known reloading powders were compared with the unfired powders. In general, the composition of the residues was similar to that found in the unfired powders. For double-base powders, comparing the ratio of the propellant (P) to the total amount of stabilizer (S) for both residue and gunpowder samples proved to be a useful measurement for identification. This P/S ratio demonstrated that the additives in the residues did not greatly change relative to the unfired powder, providing a useful indicator to aid in forensic powder and residue evaluation.     

Investigating the effect of changing ammunition on the composition of organic additives in gunshot residue (OGSR)

The measurement of the organic additives in smokeless gunpowder is an attractive approach for the detection of handgun use because it provides compositional information that can help associate residues and unfired gunpowder. We investigate several factors that will be required to advance the characterization of organic gunshot residue (OGSR) as a useful forensic tool, including evaluating residue contamination from previously fired ammunition, particle-to-particle compositional variability, and compositional features resulting from the type of firing primer used. Using ammunition loaded with known smokeless powders containing different stabilizers, a sequence of shots was fired from a .357 magnum revolver, and the muzzle exit residues were collected. Compositional analysis of the residues, both in bulk and as single particles, showed only a trace of the previously fired powder in the first shot and none in subsequent shots. In an additional experiment testing conventional leaded and the new lead-free firing primers, the OGSR composition was found not to depend on the primer type.     

Developing a quantitative extraction technique for determining the organic additives in smokeless handgun powder.

Compositional analysis of the organic additives in smokeless handgun powder can provide forensic information to associate known and questioned samples. A reliable method for the quantitative extraction of smokeless powder additives would strengthen these measurements. To achieve quantitative recovery, both supercritical fluid extraction (SFE) and ultrasonic solvent extraction (USE) were evaluated as candidate techniques. Following a detailed evaluation of the solvent choice, the recovery of spiked additive compounds, and the effect of the powder matrix, a reliable USE technique was developed. When quantitative USE recovery of the target analytes, nitroglycerin (NG), diphenylamine (DPA), and ethyl centralite (EC), is coupled with additive measurement by micellar capillary electrophoresis (CE), compositional information can be obtained in less than 1 h.     

A comparison of smokeless powders and mixtures by capillary zone electrophoresis

The analysis of inorganic ions present in smokeless and muzzleloading powders has been performed using capillary zone electrophoresis (CZE). Previous publications have examined inorganic low explosives using CZE, but have not looked at the ion profiles from smokeless powders. In this report, seven commercially available smokeless powders were analyzed as unburned powder and burned residue. The results demonstrate that ionic profiles can be used to characterize smokeless powders. Our analysis also included a smokeless powder/ Pyrodex combination to determine if smokeless powder ions are distinguishable in a mixture; however, the high concentration of ions present in Pyrodex RS prevented its detection. In addition, five different smokeless powder samples as well as Pyrodex RS were collected for analysis subsequent to deflagration in fifteen plastic pipe bombs. The relative ion concentrations between these powders can be used to illustrate the differences between open burning and pipe bomb deflagration.     

Mobile phase influence on electrospray ionization for the analysis of smokeless powders by gradient reversed phase high-performance liquid chromatography-ESIMS

The solution parameters associated with gradient elution reversed phase high-performance liquid chromatography (HPLC) were characterized by evaluating the electrospray ionization mass spectrometry (ESIMS) response of selected smokeless powder additives. Using direct liquid infusion, the positive ion ESIMS responses were determined for three general classes of powder constituents: dialkylphthalate acid esters, N,N'-dialkyl-N,N'-diphenyl urea based stabilizers and nitroso-, nitro-, and dinitro- derivatives of diphenylamine. The relative ESIMS intensities of the powder components were investigated as a function of three solution parameters: ammonium acetate concentration, pH, and percent methanol. The effect of the ammonium acetate concentration demonstrates that the electrolyte is required for efficient ionization and the ESIMS intensity was optimal at a concentration of 2mM for the selected compounds, except 2,4'-dinitrodiphenylamine. The aqueous solution pH, corresponding to the available protons in solution, did not have a significant effect on the ESIMS intensity of the analytes. The percent methanol was evaluated with both decreasing and constant electrolyte concentrations to demonstrate the effects of droplet stability and ion transfer into the gas phase. These findings were applied to the analysis of the selected smokeless powder additives using HPLC-ESIMS to illustrate increased sensitivity for the protonated molecules.     

The traces of smokeless gunpowder

The experimental investigation resulted in detection of new specific and characteristic signs of smokeless powder. Additional tests for determination and differential diagnosis of smokeless powder variants were suggested.     

A qualitative comparison of smokeless powder measurements

In the spring of 2000, the National Institute of Standards and Technology and nineteen participants conducted a comparison of smokeless powder additive compositional measurements. The purpose of this exercise was to determine the state-of-the-practice for forensic smokeless powder determinations. For the comparison, two handgun reloading powder samples were mixed and were compositionally evaluated for homogeneity by NIST. Participant laboratories included military, academic, and state/local, federal, and international forensic agencies. We solicited qualitative data identifying nitroglycerin, diphenylamine, N-nitrosodiphenylamine, and ethyl centralite. In addition, some laboratories provided identification of additional ingredients, such as nitrocellulose, or reported other measurements, such as dimensional morphology. In this paper, laboratory identification of the smokeless powder additives and a summary of the measurement methods used for the evaluations are presented. All laboratories correctly identified NG and the major stabilizers. Some disparity between laboratories was noted for the identification of minor (<0.01% by weight) stabilizers and stabilizer decomposition products.     

The Analysis of Black Powder Substitutes Containing Ascorbic Acid by Ion Chromatography/Mass Spectrometry*†

Abstract: Black powder substitutes containing ascorbic acid are a group of low explosives that utilize ascorbic acid as the fuel. The analysis of these powders is complicated by the degradation of ascorbic acid which occurs rapidly in solution and may also occur as the powder ages. Aqueous extracts of both intact powders and postblast residues were analyzed by an existing ion chromatography/mass spectrometry (IC/MS) method used at the Bureau of Alcohol, Tobacco, Firearms and Explosives. Results have shown that while ascorbic acid itself is not detected in this method, its diagnostic degradation products (threonic acid, monohydrated diketogulonic acid, and oxalic acid) can be identified. In addition, anions from the inorganic oxidizers (perchlorate and nitrate) and combustion products such as chloride, chlorate, and nitrite, can be identified within the same experiment. While this IC/MS method shows promise, future modifications are necessary because of limitations in identifying threonate in postblast residues, as well as coeluting compounds observed in postblast residues.     

Evaluation of Total Nitrite Pattern Visualization as an Improved Method for Gunshot Residue Detection and its Application to Casework Samples

Visualization of nitrite residues is essential in gunshot distance determination. Current protocols for the detection of nitrites include, among other tests, the Modified Griess Test (MGT). This method is limited as nitrite residues are unstable in the environment and limited to partially burned gunpowder. Previous research demonstrated the ability of alkaline hydrolysis to convert nitrates to nitrites, allowing visualization of unburned gunpowder particles using the MGT. This is referred to as Total Nitrite Pattern Visualization (TNV). TNV techniques were modified and a study conducted to streamline the procedure outlined in the literature to maximize the efficacy of the TNV in casework, while reducing the required time from 1 h to 5 min, and enhancing effectiveness on blood‐soiled samples. The TNV method was found to provide significant improvement in the ability to detect significant nitrite residues, without sacrificing efficiency, that would allow for the determination of the muzzle‐to‐target distance.     

Rifle wounds from high velocity, center-fire hunting ammunition.

Wounds inflicted by high velocity, center-fire rifles firing hunting ammunition are radically different from wounds caused by handguns or .22 rim-fire rifles. Injuries from pistol or .22 rim-fire bullets are confined to tissue and organs directly in the wound track. In contrast, high velocity rifle bullets can injure structures without actually contacting them. This is due to the temporary cavity produced by such missiles with the resultant shock waves having pressures of up to 200 atmospheres (20 MPa). Organs struck by such high velocity rifle bullets may undergo partial or complete disintegration. Hunting ammunition, as it passes through the body, tends to shed fragments of lead from its core, producing a characteristic snowstorm picture on X-ray. The maximum range at which powder tattooing of the skin occurs from center-fire rifles depends on the physical form of smokeless powder used as propellant. In a test with a 30-30 rifle, cartridges loaded with ball powder produced powder tattooing out to a range of 30 in. (76 cm), while similar cartridges, loaded with the traditional cylindrical powder, produced tattooing out to only 12 in. (30 cm) of range.     

Associating gunpowder and residues from commercial ammunition using compositional analysis

Qualitatively identifying and quantitatively determining the additives in smokeless gunpowder to calculate a numerical propellant to stabilizer (P/S) ratio is a new approach to associate handgun-fired organic gunshot residues (OGSR) with unfired powder. In past work, the P/S values of handgun OGSR and cartridges loaded with known gunpowders were evaluated. In this study, gunpowder and residue samples were obtained from seven boxes of commercial 38 caliber ammunition with the goals of associating cartridges within a box and matching residues to unfired powders, based on the P/S value and the qualitative identity of the additives. Gunpowder samples from four of the seven boxes of ammunition could be easily differentiated. When visual comparisons of the cartridge powders were considered in addition to composition, powder samples from all seven boxes of ammunition could be reliably differentiated. Handgun OGSR was also collected and evaluated in bulk as well as for individual particles. In some cases, residues could be reliably differentiated based on P/S and additive identity. It was instructive to evaluate the composition of individual unfired gunpowder and OGSR particles. We determined that both the numerical centroid and dispersity of the P/S measurements provide information for associations and exclusions. Associating measurements from residue particles with those of residue samples collected from a test firing of the same weapon and ammunition appears to be a useful approach to account for any changes in composition that occur during the firing process.     

Identification of ascorbic acid and its degradation products in black powder substitutes

Low explosives such as smokeless powder, black powder, and black powder substitutes have been used in illicit pipe bombings throughout the United States. Some of the newer black powder substitutes are formulated with ascorbic acid, which gradually decomposes as the powder ages, making it difficult if not impossible for the forensic chemist to identify it by traditional bulk techniques. A sensitive method for the identification of residual levels of ascorbic acid in black powder substitutes is presented. Powder samples are extracted with a mixture of acetonitrile and bis(trimethylsilyl)acetamide (BSA), which converts carboxylic acid and alcohol functional groups to trimethylsilyl esters and ethers, respectively. Samples are then analyzed by gas chromatography-mass spectrometry (GC-MS). Results have shown that trace amounts of ascorbic acid can be identified at detection limits that are well below those for traditional bulk techniques. Degradation products for ascorbic acid (hydroxylated carboxylic acids, furanones, and lactones) can also be detected.     

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).     

枪击案件中射击残留物提取方法的探讨

目的结合现场勘查提取和实验研究,探讨了几种提取射击残留物的不同方法。方法采用富集浓缩、颗粒收集等方法。结果运用上述方法提取了附着在玻璃、汽车、塑料和织物上弹孔周围的射击残留物。结论收到良好的效果,大大提高了射击残留物提取率和检出率。