Vibrational spectroscopy and chemometrics in GSR: review and current trend

Background This review represents many significant methods of chemometrics applied as data assessment methods originated by many hyphenated analytical techniques containing their application since its origin to today. Main body of the abstract The study has been divided into many parts, which contain many multivariate regression methods. The main aim of this study is to investigate the chemometrics tools used in GSR (gunshot residue) or forensic ballistics. Short conclusion As a final point, the end of part of this review deals with the applicability of chemometric methods in forensic ballistics. We select to give an elaborate description of many significant tools established with their algorithm in admire of utilizing and accepting them by researchers not very aware with chemometrics.

CRIMINALISTICS ASPECTS OF THE STUDY BALLISTIC CHARACTERISTICS AND STRIKING PROPERTIES OF BULLETS OF PISTOL CARTRIDGES OF 9 × 21 IMI CALIBER

The article presents data based on the results of experimental studies on the external ballistics parameters and the nature of changes in the trajectory of the kinetic energy of four types of pistol cartridges bullets 9 × 21 IMI (9 × 21 mm.), which were shot from two samples of carbines with different lengths of the rifled part of the barrel. Of particular interest are data on the nature of the shell interaction and expansive bullets of cartridges of the indicated caliber with the tissues of a biological object, the imitation of the interaction with which was carried out using ballistic testing backing material (ballistic clay). The use of a simulator of biological tissues of the human body made it possible to determine the features of the shock-contact interaction of shell and expansive bullets with them, as well as to establish the nature of the behavior of these bullets in the thickness of a viscoelastic medium. It was experimentally found that under certain conditions, 9 mm jacketed bullets are capable of inflicting through wounds to the human body at firing distances up to 25 m inclusive, while the bullet, after breaking through the barrier, has energy characteristics that are sufficient to inflict a penetrating injury of varying severity on another biological object. Due to the use of ballistic clay, it became possible to visualize the maximum amount of damage caused by shell and expansive bullets, as well as to determine the features of the formation of exit wounds, taking into account the destabilization of shell bullets in the thickness of the obstacle. It should be noted that at firing distances up to 5 m inclusive, shell bullets, due to the loss of gyroscopic stability in the tissues of a biological object, which have a sufficiently large thickness, are capable of inflicting wounds, the volume and severity of which are comparable to or exceed the corresponding parameters of wounds caused by expansive bullets. The obtained results of measurements of the velocity of the of shell bullets after overcoming an obstacle in the form of a viscoelastic medium can later become the basis for calculating the contact speed of a bullet with a known length of the channel of the inflicted wound. The article for the first time presents the calculated data on the parameters of the flight path of shell and expansive bullets of pistol cartridges 9 × 21 IMI (9 × 21 mm.) at firing distances up to 100 m. The presented results of experimental studies and calculated data will allow experts in the field of forensic ballistics and forensic medicine to solve the tasks set by the pre-trial investigation authorities. Key words: ballistic clay, biological object, elements of the trajectory of a bullet flight, carbine, pistol cartridge, wound, wound channel, damaging properties, damage.

Actual issues of systematization of scientific knowledge on the conditions of shot in the forensic ballistics

In this research, there was considered a challenge of constructing a system of scientific knowledge of the shot conditions in judicial ballistics. It was observed that there are underlying factors that are intended to ensureits [scientific knowledge] consistency: identification of the list of shot conditions, which require consideration when solving expert-level research tasks on weapons, cartridges and traces of their action; determination of the communication systems in the course of objects’ interaction, which present the result of exposure to the conditions of the shot; classification of the shot conditions based on the grounds significant for solving scientific and practical problems. The article contains the characteristics of a constructive, functional factor (condition) of weapons and cartridges influence, environmental and fire factors, the structure of the target and its physical properties, situational and spatial factors, and projectile energy characteristics. Highlighted are the forms of connections formed in the course of objects’ interaction, proposed are the author’s classifications of forensically significant shooting conditions with them being divided on the basis of the following criteria: production from the object of interaction, production from a natural phenomenon, production method, results weapon operation and utilization, duration of exposure, type of structural connections between interaction objects, number of conditions that apply when firing and the forming traces.

GUNSHOT INJURY: THE ROLE AND PLACE IN THE STRUCTURE OF VIOLENT DEATH, FORENSIC DESCRIPTION OF LETHAL CASES IN THE CITY OF MINSK FOR THE PERIOD 2009-2018

The article sets out the main historical milestones in the development of forensic ballistics, summarizes the literature on the incidence of lethal gunshot injuries in the world, and presents the results of our own study of deaths from gunshot injuries in Minsk from 2009 to 2018. Medical and social laws have been established on the basis of which the forensic medical characteristic of a fatal gunshot injury, compiled average statistical “portraits” of those killed as a result of this type of violent death have been drawn up. Analysis of the results of the study allows us to come to the following conclusions: – the results of statistical reports and scientific literature indicate a high level of occurrence of fatal injuries in the structure of violent death in the world, is one of the main areas studied by forensic science and practice in the study of gunshot injuries; – on the basis of a retrospective study, this forensic medical characteristic of a fatal gunshot injury in Minsk for the period from January 01, 2009 to December 31, 2018. It includes the type of death, gender, age, time of year, time of day, district of the city, place of causing gunshot injuries, presence ethyl alcohol, the place of death, the type of weapon, the type of ammunition, the type and location of the wound; – the average “portraits” of people who died in Minsk in 2009-2018 were compiled because of this type of violent death. In the “Expert Conclusion” and the decisions on the appointment of forensic medical examinations for the studied period, information about the possible ricocheting nature of the gunshot injuries was not found. This may be due to the lack of methods for establishing the fact and parameters of the ricochet of the gunshot and testifies to the need for further experimental studies in areas of forensic ballistics.

The nature of scientific knowledge on the conditions of the shot and their place in the forensic ballistics system

At this time, a scientific approach has developed in ballistics, in which the topic of the conditions of the shot is addressed only within solving its individual issues. This causes fragmentation and incompleteness of information about the conditions of a shot in judicial ballistics, hinders its development, reduces the possibility of a forensic ballistic examination in providing disclosure and investigation of crimes. In order to solve the problem, the authors examined the nature of scientific knowledge about the conditions of a shot in judicial ballistics, assessed their place in the system of judicial ballistics, identified areas of scientific knowledge that determine their content. It is established that scientific knowledge about the conditions of the shot is derived from judicial ballistics and is of a theoretical and applied nature, reflecting the principle of building knowledge, their focus on taking into account the influence of these conditions in displaying the properties and attributes of weapons, cartridges and traces of their action in solving expert problems. The process of generating information about the conditions of the shot, in addition to the scientific and methodological apparatus of forensic ballistics, determines the integration of the scientific knowledge of forensics, forensics, military equipment and forensic medicine. An element of the development of judicial ballistics is the structural isolation in it of a section containing a system of scientific knowledge about the conditions of the shot. This will allow focusing on the theoretical, methodological and organizational side of the problem, create conditions for increasing the scientific and methodological support of forensic ballistic expert studies.

DETERMINATION OF THE BALLISTIC CHARACTERISTICS AND THE DAMAGING PROPERTIES OF SELF-MADE LOADING CARTRIDGES OF 7.62*39 CALIBER

In practice of forensic medicine and forensic ballistics there are quite often the cases of different types ofgunshot wounds infliction by atypical damaging elements which were used in illegal independent loading of cartridges to the rifle weapon. The purpose of the researches being performed - studying on a concrete example from criminalistics practice of damaging properties of 7.62 mm rifle bullets of type FMJBT (Full Metal Jacketed Boat Tail) which were used for loading by self-made way cartridges of 7.62 * 39 caliber. Originally, during natural tests in the conditions of a ballistic track the ballistic characteristics of the shot bullets and the value of their ballistic coefficient were established. At the following stage of researches the losses of kinetic energy of rifle bullets on punching blocks of ballistic plasticine with the thickness of 100-140 mm were determined. As a result of tests the character of formation of the damage channel in the thickness of biological tissues simulator is established at the stable and unstable movement of the bullets in the visco elastic medium. Besides, during the researches the values of the parameters necessary for calculations ofpenetration depth of the bullets into a fabric of biological object depending on their speed at the moment of hit in the target, were determined. In particular it was established that at unstable movement of an investigated bullet in thickness of the simulator the value of boundary speed amounts 138.1 m/s, and the value of the medium drag factor - 1.782. Using estimated values offlight speed of the bullets in the trajectory the values of depth wound channels in biological tissues were calculated and the conclusion was drawn on the guaranteed causing of penetrating wounds in all established distances of shooting. Thus, use of the methodfor estimation of damaging properties of investigated bullets, the criterion of which is the length of the wound channel and its boundary value was obviously demonstrated.