Features of Detection of Handprints on Firearms and Cartridges

Introduction. Firearms and ammunition are traditionally complex objects for fingerprint identification research. Theoretical analysis. The possibilities of modern laboratory methods for detecting handprints on firearms and ammunition are discussed. It is noted that the most effective method is the vacuum deposition of thin metal films, as well as cyanoacrylic acid esters in vacuum. Technology for producing powders. A method for producing silica gel, polystyrene and aluminosilicate powders using a “micromill” is described, and particle sizes of the powder are shown. Experiment. Experiments have been carried out to detect powders of silica gel, polystyrene and aluminosilicate of hand traces on firearms and cartridges for them. Discussion of results. It was determined that the optimal laboratory method for detecting handprints on firearms and ammunition for them is the detection of cyanacrylic acid esters in a vacuum, and silica gel, polystyrene and aluminosilicate powders are effective at the scene, with silica gel being the most suitable fingerprint powder for these purposes.

Possibilities of Integrated Research into Traces and Damages Arising from Application of Electric Shock Devices

Introduction. In the investigation of criminal cases involving the use of electroshock devices (ESD), it becomes necessary to use special knowledge to determine the nature and mechanism of damage to a person’s body and clothing due to electric shock. The specificity of damage formation leads to the use of special knowledge in the form of expert studies. Such studies are possible in the form of a comprehensive forensic medical examination or in the form of a complex of forensic and forensic studies (examinations). Research and results of the study. Research methods for injuries on the human body and on items of clothing that have arisen under the influence of electric discharges of ESD are shown. The paper describes the method of obtaining experimental injuries on the studied garment, as well as the results of a comparative study of the morphological features of the investigated and experimental injuries. The possibility of damage formation on the body of the victim and on the subject of his or her clothes as a single damage with repeated exposure to damaging factors of the ESD is shown. The possibility of establishing a group affiliation of the ESD in accordance with the damage to clothing is shown. Discussion of results. The author highlights the similarity of the methodology (algorithm) for examining traces and injuries on the human body and items of clothing resulting from the use of ESD with the methodological approaches of traditional comprehensive forensic investigations of injuries on the human body and items of clothing.

A Probabilistic Assessment of the Complexes of Combined Traces in Secondary Tracks on Fired Bullets

Introduction. The paper analyzes the effectiveness of the application of the method of successively matching traces (CMS method) and the probabilistic method for substantiating the forensic identity of the overlapping secondary traces on fired bullets. Theoretical analysis. The theoretical foundations of the CMS method and the probabilistic method are considered. It is shown that the second method is formed on the basis of two mutually complementary probabilistic models. Experimental studies of the effectiveness of assessing the uniqueness of the complexes of combined tracks. The studies were conducted for secondary traces with high and low track density (for tracks on bullets fired from PM and AK-74, respectively). Potential trace identity criteria were defined for traces with low track density according to the CMS method. The authors determined the probabilistic criteria for the identity of the compared traces with high and low track density. It is shown that for traces with a low track density, the criterion of potential identity is the probability of random alignment of tracks no more than 5*10-3, and for traces with a high density of tracks the probability is no more than 10-6. Results. The probabilistic method allows you to obtain a quantitative assessment of the uniqueness of coincident features and correctly substantiate a categorical positive conclusion when identifying firearms by traces on fired bullets.

Judicial and Ballistic Examination Information Support

Introduction. Weapons are widely used in crimes. Firearms, firearms of limited destruction seized by law enforcement agencies, gas, pneumatic weapons, cartridges for the specified types of weapons, traces of a shot on various obstacles, fired bullets and other shells, fired cartridges are among the main objects of forensic ballistic examination. Theoretical analysis. Forensic ballistic expertise is carried out strictly in accordance with the expert methods. The effectiveness of solving diagnostic and identification problems depends on the relevance, reliability, availability of reference information on firearms and other weapons, ammunition for these weapons, and other objects. In the process of expert research, various information systems of identification and non-identification (reference) purposes are used. Empirical analysis. The potential capabilities of information systems are not fully utilized due to various circumstances, including: fragmentation, special access to information resources, limited functionality of existing identification ballistic systems, insufficiently effective search algorithms, etc. Results. In order to eliminate these and other circumstances, it is proposed to combine the most relevant and sought-after arrays of information about firearms and other weapons, ammunition to it, and other data relevant to forensic ballistics into a single information system based on automated search tools with the prospect of introducing artificial intelligence technologies expertise.

Research into Morphological Signs Arising When Shooting from Snoothbore Hunting Weapon at Glass from Triplex

Introduction. Automobile windshields act as objects of research in various categories of cases – criminal, civil, etc. The information obtained in the study of such objects is of important evidentiary value. From the forensic point of view, the windshields of automobiles, which are made of triplex and have physico-mechanical and consumer characteristics that are different from ordinary glasses, are of the greatest interest. Theoretical analysis. The article is devoted to the analysis of morphological features that occur when shooting from a smoothbore hunting rifle into the windshield of a car with various types of shells and from different distances. The triplex design implies a special fracture pattern, which is formed by a multilayer structure, moreover, the polymer layer does not allow broken fragments to crumble. The author analyzed the characteristics of the features that allow, with a high degree of certainty, to quickly determine the approximate direction of projectile approach and the distance of the shot. Discussion of results. On the basis of the study of morphological signs that occur when shooting from a smoothbore hunting weapon into a car windshield from triplex, the direction of projectile approach to the glass is determined, as well as the differences in damage caused by different shells and the same shells, but from different distances.

Identification of Similar Images of Breech Face Impressions by the Correlation Cells Method

Introduction. The current task of forensic ballistic identification is to investigate the breech face impressions on the firing cartridge cases. The paper deals with comparison of images of breech face impressions by correlation cells method. Theoretical analysis. Similarity of images of investigated impressions can be established by a method of the correlation analysis. However, this method is ineffective, because the correlation coefficient is dominated by areas that do not contain useful information. To improve the efficiency of correlation analysis, J. Song proposed a method of congruent matching cells. The method of correlation cells is based on this method. The paper presents the algorithm of the method, broken down into the main stages. The first stage includes preliminary processing of the image and splitting it into cells. The second stage is building the distribution of the maximums of correlation coefficients. The third stage is to establish the presence of the cluster in the graph of this distribution. The fourth stage allows to identify areas valid for further work. The method of selecting areas that do not contain breech face impressions is based on finding the autocorrelation function. In the fifth stage, the final value of the correlation coefficient is calculated without taking into account the areas of the analyzed images that do not contain useful information. Experimental research. Two conditions were proposed as criteria for similarity of the breech face impressions. The first one is a high value of the correlation coefficient. The second is the presence of the cluster on the graph of maximum correlation coefficient distribution. The verification of this fact is based on the identification of the likelihood coefficient. Conclusion. The method of correlation cells made it possible to increase the efficiency of the correlation analysis. In the course of the work, the criteria for attributing impressions to the category of similar ones were defined. 

Regularities of Traces Formation on the Reloaded Cases During the Discharge of a Firearm

Introduction. In connection with legalization of autonomous cartridges loading to the rifled firearm, the matter of forensic examination of reloaded cases is growing more urgent. Objectives. The research is aimed at studying the regularities of trace formation on the reloaded cases during the shot from the firearm in order to diagnose the technique of cartridges producing, these cases being the cartridges parts. Experimental part. Examining the traces formed in the course of a shot and reloading was carried out with hunter’s .300 win mag caliber cartridge cases ejected from .300 win mag caliber Sauer 202 carbine. Discussion of results. There are already some traces on the surface of reloaded cases formed by the reloading equipment. This is their specific feature. During the shot, the firearm traces are deposited on them. The form and isolation of traces of reloading equipment and parts of the firearm are similar because the mechanism of their formation is analogous. They are formed during the process of local physical action either as the pressure of a trace forming object or its sliding. The traces on the shoulder and liner flange of cases are the most informative ones. Differentiation of these traces, understanding of the regularities of their formation are necessary for ascertaining the fact of cases reloading. The traces of equipment prove the homemade technique of cartridges making, the examined reloaded cases being their parts.

The Study of Traces on Spent Cartridges from Modern Modifications of Individual Models of Automatic Pistols

Introduction. One of the main ways to identify weapons in a forensic examination is to study the traces left on the cartridges. As a result of the examination, it is possible to receive answers to questions related to the model and a specific weapon. In this regard, information on traces and trace details for new models of firearms and the latest modifications of well-known models becomes relevant (manufacturers update the produced weapon approximately every 5–10 years). Experimental part. The experiment was carried out in the conditions of a shooting gallery; in total, about 200 rounds of 9×19 mm caliber (Parabellum) were shot from the following models of pistols: Glock 17, Glock 34, Beretta 92 FS, MP-446 Viking. Each model of the weapon was presented in three copies, for shooting of each copy no less than 10 cartridges were used, the case of the top cartridge in the magazine for 12 o'clock position was marked with white paint. Traces on the cartridge cases were examined visually and under a microscope with a magnification of 20× and 40×. Discussion of results. The trace pattern on the experimentally obtained spent cartridge cases corresponded mainly to the reference data. A trace from Glock 17 and Glock 34 was found at the bottom of the cartridge case from the tip of the striker that was not connected with firing-pin impression that is not listed in the reference book. This track has a large variation depending on the rate of fire (this is due to the different heating of the weapon). The trace from the front part of the ejector hook from Beretta 92 FS, that is not described in the reference book, was found at the bottom of the cartridge case at 4 o'clock position. The marks on the cartridge cases of the shotguns of the Viking MP-446 differ from the ones described in reference books by the presence of the traces of processing of the cartridge stop and the trace from the striker tip on the primer, which is not related to the cap of the primer, showing variability depending on the rate of fire. Conclusions. The obtained trace images of signs on the cartridge cases of modern modifications of the known models of firearms allow us to specify the definition of the model of the weapon according to group attributes. Using the data obtained, it is possible to identify the rate of firing of weapons at the scene of the accident in the absence of the weapon by following the tracks on the cartridges. The traces on the cartridge cases, that were obtained during the experiments and are not described in the literature on forensic issues, have individual characteristics and can be used for identification. The dependence of the trace formation on the rate of fire correlates with the recommendation for obtaining cartridge cases for a comparative study of a combined firearm: first, one should fire the cartridges in the single-fire mode, and then in bursts. For self-loading weapons, it can also be recommended to vary the rate of fire when experimentally obtaining cartridge cases for comparative research.

Current Issues of Forensic Investigation of Traces on Bullets and Cartridge Cases Formed During the Shot of Civilian Firearms Manufactured on the Basis of Combat Samples

Introduction. This article deals with some issues of forensic investigation of civilian firearms manufactured based on combat samples: features of trace formation on bullets and cartridge case design changes of the original models (samples) of the firearms. The authors highlight the problem of the lack of a literary base and illustrative material, necessary for carrying out diagnostic research of traces on bullets and cartridge cases formed when fired from civilian firearms manufactured on the basis of samples of military weapons. Theoretical analysis. The paper analyzes data of weapons factories, as well as weapons they produce. The authors focus on the necessary terms and examples of the weapon, the design of which was modified and is different from the sample combat weapons. The paper looks at the main provisions of some normative and legal acts of the Russian Federation. Results. The authors identified the groups of traces, formed after firing redesigned weapons, and the place of the location on the surface of bullets and casings.

The Need for the Development of Basic Provisions and the Conceptual Terminological Apparatus of the Scientific and Practical Knowledge in New Sphere of “Pseudo-Legal Turnover of Potentially Dangerous Materials, Substances and Products...”

Introduction. The article is devoted to the issues of pseudolegal turnover of potentially dangerous materials, substances and products as a source of formation of means of mass destruction of people while committing crimes of sabotage and terrorist orientation. Theoretical analysis. The causes and genesis of the pseudo-legitimate turnover of edged weapons, barrelled gas weapon and firearms, new psychoactive substances with nonspecific increased toxicity or other pronounced damaging features are revealed in detail. This article formulates recommendations for the prompt identification of relevant threats during forensic medical, forensic chemical, forensic ballistic and other types of examinations, the development of preventive measures, including proposals to improve existing legislation. The authors consider these problems in the context of the main provisions of the Decree of the President of the Russian Federation of March 11, 2019 No. 97 “Fundamentals of State Policy of the Russian Federation in the field of ensuring chemical and biological safety...”. Results. The authors provide justification for the need for unification, primarily of the conceptual and terminological apparatus and methodological foundations of a forensic expert study in the circumstances of the pseudo-legal turnover of potentially dangerous materials, substances and products (PDMSP), taking into account the possibilities of the integrated use of the achievements of various areas of scientific and practical knowledge.