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Ballistics (the linkage of bullets and cartridge cases to weapons) is a common type of evidence encountered in criminal cases around the world. The interest lies in determining whether two bullets were fired using the same firearm. This paper proposes an automated method to classify bullets from surface topography and Land Engraved Area (LEA) images of the fired pellets using machine and deep learning methods. The curvature of the surface topography was removed using loess fit and features were extracted using Empirical Mode Decomposition (EMD) followed by various entropy measures. The informative features were identified using minimum Redundancy Maximum Relevance (mRMR), finally the classification was performed using Support Vector Machines (SVM), Decision Tree (DT) and Random Forest (RF) classifiers. The results revealed a good predictive performance. In addition, the deep learning model DenseNet121 was used to classify the LEA images. DenseNet121 provided a higher predictive performance than SVM, DT and RF classifiers. Moreover, the Grad-CAM technique was used to visualise the discriminative regions in the LEA images. These results suggest that the proposed deep learning method can be used to expedite the linkage of projectiles to firearms and assist in ballistic examinations. In this work, the bullets that were compared were air pellets fired from both air rifles and a high velocity air pistol. Air guns were used to collect the data because they were more accessible than other firearms and could be used as a proxy, delivering comparable LEAs. The methods developed here can be used as a proof-of-concept and are easily expandable to bullet and cartridge case identification from any weapon. • The classification of bullets based on LEA topography using machine learning. • Features were extracted using Empirical Mode Decomposition and entropy measures. • Bullet classification was performed using the whole image of LEA and deep learning. • DenseNet121 provided high classification performance. [ABSTRACT FROM AUTHOR]

The detection and interpretation of gunshot residue (GSR) can play an important role in the investigation of firearm related incidents. Recently, the potential of organic compounds to provide an additional means to discriminate between GSR and environmental particles, in particular in cases where lead-free ammunition is used, has been highlighted. This work describes a method for the extraction and detection of complementary organic and inorganic compounds from a single GSR sample, using a methodology that makes implementation in the current standard procedure feasible. GSR samples were collected from the shooter's hands following double and single discharges, using the traditional adhesive carbon aluminium stubs. Analysis of organic compounds was performed using solid-phase microextraction gas chromatography mass spectrometry (SPME-GC-MS), followed by analysis of the traditional inorganic particles using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). Detection of both categorised organic GSR compounds (e.g. ethyl centralite, diphenylamine and 2-nitrodiphenylamine) and characteristic inorganic GSR has been achieved. Given the fact that the detected organic GSR compounds are relevant with respect to the confirmation of GSR materials, this method has successfully demonstrated the ability to obtain a total chemical profile from a single GSR sample, which has the potential to increase the probative value of GSR evidence. [ABSTRACT FROM AUTHOR]

There has recently been an increase in the research and implementation of advanced measurement techniques to ballistic toolmark identification. This has led to a shift from greyscale imaging to the acquisition of dense areal datasets. With the addition of mathematical correlation algorithms, these advanced techniques will be advantageous in criminal investigation. However, with the use of areal topography comes the addition of height point data which may differ in primer caps of varying material composition. This study discusses the differences in the overall topography of firing pin impressions in different primer cap materials, and the effect it has on the successful correlation of ballistic toolmark evidence. [ABSTRACT FROM AUTHOR]

The insufficient recognition of injuries by the BB-gun (regarded as toys for children) has led to its increasing misuse without permission, which has caused many public safety issues. Aiming to enhance the understanding of the injuries by the BB-gun, the experimental and numerical study of BB-Gun pellet penetrating "cowhide + gelatine" composite target was comprehensively carried out. It was confirmed from the experiment that BB-Gun is capable of inflicting severe or fatal wounds to important organs, and perforating the skin or not could be employed to evaluate the safety of BB-guns. Moreover, three forms of ballistic limit (including: velocity, kinetic energy and specific kinetic energy) of typical BB were calculated and analyzed by reasonably validated numerical simulation method. Additionally, a formulation was acquired by dimensional analysis based on the simulation results and was verified to accurately predict the ballistic limit velocity of BB with different mechanical properties. The method may help to improve the understanding on the minimal velocity needed to perforate skin and may be advised as the determination of the safety of BB-gun. [ABSTRACT FROM AUTHOR]

In this paper, the effect of the chemical composition of .22LR bullets was studied and correlated to the extent and quality of the markings left after shooting them with the same gun. Scanning electron microscopy and optical comparator microscopy equipped with 3D and profilometry modules were used as non destructive techniques with two main purposes. The first is to assist the firearm examiner in the choice of the ammunition most suitable for preparing the test bullets. The second is to propose an approach, crossing data from optical microscopy, profilometry and space-resolved chemical analysis, for explaining the morphology of striae, whether continuous or interrupted. Among the most notable results is the finding that commercial .22LR ammunition show very wide interbrand, interlot and intralot variability. A selection of test ammunition solely based on the same brand and model used on the crime scene is therefore not suitable, urging the need for a more accurate choice, based on a preliminary chemical analysis. [ABSTRACT FROM AUTHOR]

Synthetic models, also called "surrogates", are commonly used in wound ballistics in order to simulate human tissues. Despite several surrogates are worldwide accepted and used; some of them have not been yet fully validated and their limits for forensic reconstructions have not been deeply investigated yet. In this work we present a homicide/suicide case involving three gunshots to the head with bullets retained in the skull or beneath the scalp. Reconstruction of these cases was performed preparing three individual synthetic head models based on post-mortem computed tomography (PMCT) measurements. Ballistic soap, polyurethane plates and 10% ballistic gelatine at 4°C were used as simulants in individually adapted thickness. Ballistic tests were performed using the questioned firearm and ammunition type. The damages on the synthetic models have been compared to the findings in PMCT and autopsy of the victims. Although the results highlighted general similarities in terms of injury characteristics, some of the experimental shots overpenetrated. Furthermore, the bullets recovered in the synthetic models did not show the same quality of deformations as the questioned bullets. This lack of bullet deformation in the synthetic models might be mainly attributed to the physical difference between real bones and polyurethane surrogate. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fingermark development techniques for brass cartridge cases/plates were evaluated. • The sequence CA + GB + fluorescent dye (BY40 or Ardrox) presented the best results. • The application of the entire sequence of developers is strongly recommended. • The gaseous blowback is the main firing effect on the deterioration of fingermarks. • Handling cartridges when loading a gun has a significant influence on the fingermarks. Abstract A study was undertaken wherein different fingermark developers were evaluated for the recovery of fingermarks from brass cartridge cases, besides the evaluation of factors such as firing effects and surface characterization of the cases. The latent fingermarks on α-brass plates, fired and unfired cartridge cases were deposited and aged for 1–14 days before development with different developers. In order to mimic the fired cartridge case conditions, the brass plates were heated and examined at room temperature (RT), at 63 and at 200 °C. The sequential treatment with cyanoacrylate, gun blue and fluorescent dye has been found to be the best among other developers for the recovery of latent fingermarks on brass surfaces including fired and unfired cartridge cases. Cartridge cases and other brass surfaces were also analyzed by surface characterization methods, including X-ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectroscopy and metallographic examination. The tested surfaces correspond to α-phase brass Cu 0.7 Zn 0.3 composition and have shown different surface morphologies (such as grain structure) and different levels of oxidation, even for cartridge cases obtained from the same batch. Due to this, the effectiveness of a given reagent for a specific brass surface is uncertain. Therefore, the application of the entire tested sequence of developers is strongly recommended. Further, the effects of firing on fingermarks on cartridge cases were examined, and the results indicated that the blowback of hot gases through the looseness between cartridge case and chamber wall of the firearm is the main cause responsible for deterioration of fingermarks during firing. Despite the recognized damage caused to fingermarks by the firing effects, good quality fingermarks were recovered from fired cartridge cases in which full fingermarks were intentionally deposited prior to firing. This indicates that the handling of the cartridges before and during the loading of the gun may have a strong influence on the quantity and quality of fingermarks, and that the firing itself is not the main responsible factor for the absence or low quality of fingermarks, as frequently reported in fired cartridge cases studies. [ABSTRACT FROM AUTHOR]

Firearm injuries are common in the world today, in both military and civilian settings. Research into the effects different ammunition has on the human body has been conducted using tissue simulants such as Ballistics Ordnance Gelatine. Previous research has found that with low velocity projectiles, the tissue simulants only represent a selected few organs, as the human body and its organs/tissues are not homogeneous. The aim of this research was to determine which ballistic simulants best represent the abdomen and thorax, for the purposes of anatomical modelling. A mounted firearm was used to fire specially made ammunition containing a sabot and steel spherical projectile at medium (∼500m/s) and high (∼900m/s) velocities. Test specimens of 50mm cube porcine tissues (lung, liver, kidney and heart) and ballistics simulants (20% and 10% Ballistics Gelatine and Clear Gel) were shot at and the energy loss determined using Doppler radar, optical infra-red sighting screens and high speed video. This study determined that the conclusions drawn from studies in these tissue simulants may not be an accurate representation of what occurs in human tissues and that different impact velocities produce differing results. New simulants are required to better represent the energy loss of a projectile through the organs of the abdomen and thorax and the results of this study may guide this development. Further experiments will be required to determine different concentrations of gelatine and their accuracy at representing the heterogeneous nature organs of the human body. [ABSTRACT FROM AUTHOR]

Gun violence is a global phenomenon with regional variation in frequency and severity. Handguns are often used in violent deaths such as suicides and homicides. Hence, ballistic trauma is a critical subject of forensic investigations. Trauma patterns are fundamental evidence for the reconstruction of the incident and for the determination of the manner of death. This study investigated the differences in trauma patterns with a series of experiments using six different calibers (.22 LR, .38 Special, .380 ACP, 9×19mm, .40 S&W, and .45 ACP) and four different bullet types. Synbone® spheres (polyurethane bone proxies) were used for close range 30cm simulated executions. The polyurethane spheres constitute an excellent proxy for human crania at the macroscopic level as suggested by other studies. The results showed that the radius of the entrance wound is positively correlated (Pearson's correlation coefficient R=0.846, p<0.05) with the caliber dimension. As muzzle velocity increased, endocranial beveling increased. Bullet weight, conversely, does not seem to have an effect on the size of the endocranial beveling present in Synbone® spheres. The ballistic experiments exhibited similarities in entrance wound morphology; radial and concentric fracture patterns, hydraulic burst effect, circumferential delamination, and endocranial beveling with that of documented forensic cases with corresponding caliber shot. Synbone spheres seem appropriate for ballistic simulations of cranial injuries; yet, more research is needed to verify these observations. [ABSTRACT FROM AUTHOR]

The Congruent Matching Cells (CMC) method was invented at the National Institute of Standards and Technology (NIST) for accurate firearm evidence identification and error rate estimation. The CMC method is based on the principle of discretization. The toolmark image of the reference sample is divided into correlation cells. Each cell is registered to the cell-sized area of the compared image that has maximum surface topography similarity. For each resulting cell pair, one parameter quantifies the similarity of the cell surface topography and three parameters quantify the pattern congruency of the registration position and orientation. An identification (declared match) requires a significant number of CMCs, that is, cell pairs that meet both similarity and pattern congruency requirements. The use of cell correlations reduces the effects of "invalid regions" in the compared image pairs and increases the correlation accuracy. The identification accuracy of the CMC method can be further improved by considering a feature named "convergence," that is, the tendency of the x-y registration positions of the correlated cell pairs to converge at the correct registration angle when comparing same-source samples at different relative orientations. In this paper, the difference of the convergence feature between known matching (KM) and known non-matching (KNM) image pairs is characterized, based on which an improved algorithm is developed for breech face image correlations using the CMC method. Its advantage is demonstrated by comparison with three existing CMC algorithms using four datasets. The datasets address three different brands of consecutively manufactured pistol slides, with significant differences in the distribution overlap of cell pair topography similarity for KM and KNM image pairs. For the same CMC threshold values, the convergence algorithm demonstrates noticeably improved results by reducing the number of false-positive or false-negative CMCs in a comparison. [ABSTRACT FROM AUTHOR]

The mechanism of injury for fractures to long bones has been studied for both direct ballistic loading as well as indirect. However, the majority of these studies have been conducted on both post-mortem human subjects (PMHS) and animal surrogates which have constraints in terms of storage, preparation and testing. The identification of a validated bone surrogate for use in forensic, medical and engineering testing would provide the ability to investigate ballistic loading without these constraints. Two specific bone surrogates, Sawbones and Synbone, were evaluated in comparison to PMHS for both direct and indirect ballistic loading. For the direct loading, the mean velocity to produce fracture was 121 ± 19 m/s for the PMHS, which was statistically different from the Sawbones (140 ± 7 m/s) and Synbone (146 ± 3 m/s). The average distance to fracture in the indirect loading was .70 cm for the PMHS. The Synbone had a statistically similar average distance to fracture (.61 cm, p=0.54) however the Sawbones average distance to fracture was statistically different (.41 cm, p<0.05). Fractures patterns were found to be comparable to the PMHS for tests conducted with Synbones, however the input parameters were slightly varied to produce similar results. The fractures patterns with the Sawbones were not found to be as comparable to the PMHS. An ideal bone surrogate for ballistic testing was not identified and future work is warranted. [ABSTRACT FROM AUTHOR]

The objective of the study is to better understand how blunt projectile ballistic parameters and material properties influence the events leading to injuries. The present work focuses on lateral thoracic impacts and follows an experimental approach. The projectiles are made with a soft foam nose assembled with a rigid rear plastic part. The dynamic properties of the foams were first determined using the Split Hopkinson Pressure Bar (SHPB) system. The impact forces on a rigid wall were then measured to provide reference load data. Lastly, shots were made on isolated thoraxes of porcine cadavers to investigate the response in the vicinity of the impact (wall displacements, rib accelerations and strains, rib fractures). Results show that the severity of the response appears to be mainly correlated with the impulse and with the pre-impact momentum. [ABSTRACT FROM AUTHOR]

Almost 60 years after the assassination of President John F. Kennedy in 1963, the majority of Americans are still reluctant to believe official reports presented by the commissions gathered in 1964 and again in 1976 that determined the direction of the shot resulting in the fatal head injury. Long-withheld, confidential government files released in 2017 reignited the controversy. The present investigation computationally simulated projectile-skull-impacts from the direction specified in official reports and from three other directions. Detailed geometric models of the human head and ammunition, as well as known parameters from the assassination site served as the supportive base for analysis. Constitutive mathematical models for the impact of projectile material with skull tissues at supersonic speed were employed to analyze bone and bullet fragmentation mechanics. Simulated fracture characteristics of bone and bullet were compared with photographic and X-ray evidence. The most likely origin of the fatal shot was determined based on the degree of corresponding deformation and fragmentation between simulation and documented evidence. Computational corroboration could be established as physically consistent with high-speed impact from the rear, as established by the official commissions. Simulations of three other speculative shot origins did not correspond with the documented evidence. [ABSTRACT FROM AUTHOR]

A reference ballistic image database (RBID) contains images of cartridge cases fired in firearms that are in circulation: a ballistic fingerprint database. The performance of an RBID was investigated a decade ago by De Kinder et al. using IBIS1 Heritage™ technology. The results of that study were published in this journal, issue 214. Since then, technologies have evolved quite significantly and novel apparatus have become available on the market. The current research article investigates the efficiency of another automated ballistic imaging system, Evofinder1 using the same database as used by De Kinder et al. The results demonstrate a significant increase in correlation efficiency: 38% of all matches were on first position of the Evofinder correlation list in comparison to IBIS1 Heritage™ where only 19% were on the first position. Average correlation times are comparable to the IBIS1 HeritageTM system. While Evofinder1 demonstrates specific improvement for mutually correlating different ammunition brands, ammunition dependence of the markings is still strongly influencing the correlation result because the markings may vary considerably. As a consequence a great deal of potential hits (36%) was still far down in the correlation lists (positions 31 and lower). The large database was used to examine the probability of finding a match as a function of correlation list verification. As an example, the RBID study on Evofinder1 demonstrates that to find at least 90% of all potential matches, at least 43% of the items in the database need to be compared on screen and this for breech face markings and firing pin impression separately. These results, although a clear improvement to the original RBID study, indicate that the implementation of such a database should still not be considered nowadays [ABSTRACT FROM AUTHOR]

The number of head wounds due to firearms remains low in France because these cases are primarily linked to suicide (or attempted suicide) and, to a lesser extent, to attacks or hunting accidents [1]. Characterized by the impact of a projectile, which in most cases is made of metal, at high levels of kinetic energy, such acts generally result in severe trans-cerebral lesions with significant levels of morbidity/mortality [2]. Seldom are cases reported in the literature that give a detailed study of intracranial foreign bodies made of bone in such situations [3]. Here we report on the case of two suicides resulting from a transcranial gunshot wounds caused by weapons and ammunition issued by the French police force. Each case helped distinguish a characteristic bone fragment, in the form of a "patch", equivalent in size to the caliber of the bullet. [ABSTRACT FROM AUTHOR]

The one-by-one examination of the increasing Open Case File (OCF) archive by comparison macroscope has become a time-consuming process and the last quarter of the 20th century witnessed the development of automated ballistic identification systems. After the utilization of these systems, government institutes, scholars and the companies devising such systems conducted various performance tests to analyze duration and correlation. The performance of BALİSTİKA and similar automated firearms identification systems are frequently measured using the pistol cartridges. This study brings a new perspective to automated ballistic identification system performance tests through using same and different brand steel 7.62 × 39 mm cartridge cases. The performance of BALİSTİKA system was measured using 4387 comparison cartridge cases according to breech face, firing pin, ejector marks and combined evaluation criteria. It was determined that correlation performance of BALİSTİKA for the same brand cartridges are higher and ejector marks are the most distinct matching criteria for 7.62 × 39 mm steel cartridge cases. The test results are presented under the headings of weapon-manufacturer countries, automated ballistic identification system matching criteria for both same and different cartridge brands. [ABSTRACT FROM AUTHOR]

Abstract: Although the benefits of the use of less lethal kinetic energy munitions are numerous, there is a need to evaluate the munitions prior to deployment to ensure their intended effect. The objective of the current research was to validate a surrogate that could be used to predict the risk of penetration of these devices. Existing data from biomechanical testing with post-mortem human specimens (PMHS) served as the foundation for this research. Development of the surrogate involved simulating the various layers of the skin and underlying soft tissues using a combination of materials. A standardized 12-gauge impactor was used to assess each combination. The energy density that resulted in a 50% risk of penetration for the anterior thorax region (23.99J/cm2) from the previous research was matched using a specific combination of layers. Twelve various combinations of materials were tested with the 50% risk of penetration determined. The final validated surrogate consisted of a Laceration Assessment Layer (LAL) of natural chamois and .6cm of closed-cell foam over a Penetration Assessment Layer (PAL) of 20% ordnance gelatin. This surrogate predicted a 50% risk of penetration at 23.88J/cm2. Injury risk curves for the PMHS and surrogate development work are presented. [Copyright &y& Elsevier]

Abstract: The present study aimed determines lead (Pb), antimony (Sb) and barium (Ba) as the major elements present in GSR in the environmental air of the Ballistics Laboratory of the São Paulo Criminalistics Institute (I.C.-S.P.), São Paulo, SP, Brazil. Micro environmental monitors (mini samplers) were located at selected places. The PM2.5 fraction of this airborne was collected in, previously weighted filters, and analyzed by sector field inductively coupled plasma mass spectrometer (SF-HR-ICP-MS). The higher values of the airborne lead, antimony and barium, were found at the firing range (lead (Pb): 58.9μg/m3; barium (Ba): 6.9μg/m3; antimony (Sb): 7.3μg/m3). The mean value of the airborne in this room during 6 monitored days was Pb: 23.1μg/m3; Ba: 2.2μg/m3; Sb: 1.5μg/m3. In the water tank room, the air did not show levels above the limits of concern. In general the airborne lead changed from day to day, but the barium and antimony remained constant. Despite of that, the obtained values suggest that the workers may be exposed to airborne lead concentration that can result in an unhealthy environment and could increase the risk of chronic intoxication. [Copyright &y& Elsevier]

Abstract: For crime scene investigation in cases of homicide, the pattern of bloodstains at the incident site is of critical importance. The morphology of the bloodstain pattern serves to determine the approximate blood source locations, the minimum number of blows and the positioning of the victim. In the present work, the benefits of the three-dimensional bloodstain pattern analysis, including the ballistic approximation of the trajectories of the blood drops, will be demonstrated using two illustrative cases. The crime scenes were documented in 3D, using the non-contact methods digital photogrammetry, tachymetry and laser scanning. Accurate, true-to-scale 3D models of the crime scenes, including the bloodstain pattern and the traces, were created. For the determination of the areas of origin of the bloodstain pattern, the trajectories of up to 200 well-defined bloodstains were analysed in CAD and photogrammetry software. The ballistic determination of the trajectories was performed using ballistics software. The advantages of this method are the short preparation time on site, the non-contact measurement of the bloodstains and the high accuracy of the bloodstain analysis. It should be expected that this method delivers accurate results regarding the number and position of the areas of origin of bloodstains, in particular the vertical component is determined more precisely than using conventional methods. In both cases relevant forensic conclusions regarding the course of events were enabled by the ballistic bloodstain pattern analysis. [Copyright &y& Elsevier]

Abstract: Introduction: Blank cartridge actuated dummy launching devices are used by migratory bird hunters to train dogs to retrieve downed birds. The devices create a loud noise while simultaneously propelling a hard foam dummy for retrieval. A newly developed dummy launcher is based on a modified cal. 9mm P.A. blank handgun with an extension tube pinned and welded to the barrel imitation. Currently, there are no experimental investigations on the ballistic background and trauma potential of these uncommon shooting devices. Methods: An experimental test set-up consisting of a photoelectric infrared light barrier was used for measurement of the velocity of hard foam dummies propelled with an automatic dummy launcher. Ballistic parameters of the dummies and an aluminium sleeve as improvised projectile (kinetic energy (E), impulse (p), energy density (E′) and threshold velocity () to cause penetrating wounds as a function of cross-sectional density (S)) were calculated. Results: The average velocity () of the dummies was measured 25.71m/s exerting an average impulse (p) of 3.342Ns. The average kinetic energy (E) was calculated 43.04J with an average energy density (E′) of 0.069J/mm2. The average velocity () of the aluminium sleeves as improvised projectiles was measured 79.58m/s exerting an average impulse (p) of 2.228Ns. The average kinetic energy (E) of the aluminium sleeves was calculated as 88.70J with an average energy density (E′) of 0.282J/mm2. Conclusion: The energy delivered by these shooting devices is high enough to cause relevant injuries. The absence of skin penetration must not mislead the emergency physician or forensic expert into neglecting the potential damage from these devices. [Copyright &y& Elsevier]

Abstract: Introduction: Cal. 9mm×17mm industrial blank cartridges deserve special interest in the field of forensic ballistic. This calibre is most often used in Kerner-type livestock stunners, but also in different power tools. The legal framework of these industrial blank cartridges is provided by the C.I.P. and DIN 7260 regulations. The aim of this investigation is to describe and compare two experimental test procedures for measurement of maximum gas pressure and kinetic energy of cal. 9mm×17mm industrial blank cartridges according to standardized C.I.P. and DIN 7260 protocols and to provide these ballistic data. Methods: Using two different pressure measurement barrels and standardized test projectiles, the maximum gas pressure and the kinetic energy of the test projectiles are investigated. While the pressure take-off point in C.I.P. protocol is at the cartridge mouth, the DIN 7260 protocol is modified using a pressure take-off point in the cartridge chamber. For each test protocol (C.I.P. and DIN), maximum gas pressure, velocity, impulse and energy of the test projectiles are measured. Each ten cartridges from the same ammunition lot of four different energy levels (red, blue, yellow, green) are investigated. Results: While the cartridge energy values are comparable between the two different test protocols, maximum gas pressure measured in the DIN set-up (3907bar) far surpasses the gas pressure in the C.I.P. protocol (1586bar). Both test protocols observed higher energy values of the green and yellow cartridges than regulated in DIN 7260. Conclusion: Enormous gas pressure values of more than 3900bar emphasize the power of industrial blank cartridges. Once again, the harmlessness of these blank cartridges and the weapons/tools that are operated with these propellants is refuted. [Copyright &y& Elsevier]

Abstract: Introduction: Vole captive bolt devices are powder actuated spring guns that are used as a pest control mean. After having triggered the explosion of the blank cartridge by touching a metal ring around the muzzle, the vole is killed by the massive propulsion of the gas jet. Improper use and recklessness while handling these devices may cause severe injuries with the hand of the operator at particular risk. Currently, there are no experimental investigations on the ballistic background of these devices. Methods: An experimental test set-up was designed for measurement of the firing pressure and the dynamic force of the gas jet of a vole captive bolt device. Therefore, a vole captive bolt device was prepared with a pressure take-off channel and a piezoelectric transducer for measurement of the firing pressure. For measurement of the dynamic impact force of the gas jet an annular quartz force sensor was installed on a test bench. Each three simultaneous measurements of the cartridges’ firing pressure and the dynamic force of the blast wave were taken at various distances between muzzle and load washer. Results: The maximum gas pressure in the explosion chamber was up to 1100bar. The shot development over time showed a typical gas pressure curve. Flow velocity of the gas jet was up to 2000m/s. The maximum impact force of the gas jet at the target showed a strong inverse ratio to the muzzle''s distance and was up to 11,500N for the contact shot distance. Energy density of the gas jet for the close contact shot was far beyond the energy density required for skin penetration. Conclusion: The unique design features (short tube between cartridge mouth and muzzle and narrow diameter of the muzzle) of these gadgets are responsible for the high firing pressure, velocity and force of the gas jet. These findings explain the trauma mechanics of the extensive tissue damage observed in accidental shots of these devices. [Copyright &y& Elsevier]

Explosion-related deaths are a disregarded topic of forensic sciences, despite the pivotal role of the forensic pathologist in such investigations. In fact, very few scientific articles have been published up to now, even if there is a considerable increase of terrorist attacks worldwide due to the use of improvised explosive devices (IEDs). In this paper, the authors show a retrospective autopsy-based study on the two major civilian terrorist events which occurred in Milan (Italy). The first one took place in a closed system, where a gelignite bomb was set inside the National Agriculture Bank in December 1969. 17 people were killed, and all of them underwent forensic autopsies, which were performed at the Milan Institute of Legal Medicine. The second event took place in an open system, where a car bomb exploded in Palestro Street in July 1993. 5 people were killed, forensic autopsies were performed as well. A total of 22 explosion-related deaths were assessed in this study. For each victim, the analysis of clothes, external and internal examinations were reported; furthermore, a statistical analysis using Fisher's exact test was carried out in order to show differences among blast injuries that occurred in a closed system versus an open system. The analysis of the autopsy reports, which included the descriptions of clothes, and the injury patterns allowed a possible reconstruction of the bodily exposure side of the victims in relation to the origin site of the explosive devices. [ABSTRACT FROM AUTHOR]

Evaluation of cartridge cases is essential within forensic ballistic analysis and is used in an attempt to establish a connection to the weapon used to fire it. This study consists of two experiments. The aims of Experiment 1 were to establish whether micro-CT is appropriate and repeatable for ballistic cartridge case analysis and if measurements can be extracted repeatably and reliably. Experiment 2 aimed to compare cartridge cases from two weapons to establish the magnitude of variation within and between weapons. A total of 48 cartridge cases fired by two distinct weapons were collected and micro-CT scanned to a high resolution. One randomly selected cartridge was scanned ten times under the same conditions to ensure repeatability of the scanning conditions in Experiment 1. Three novel measurements to quantitatively assess the firing pin impressions were proposed in Experiment 1 and comparatively analysed from two weapons in Experiment 2. Experiment 1 showed that micro-CT is an effective and highly repeatable and reliable method for 3-dimensional imaging and measurement of ballistic cartridge cases. Furthermore, high agreement for inter-rater reliability was found between five raters. Quantitative micro-CT analysis of the firing pin impression measurements in Experiment 2 showed a significant difference between the two studied weapons using Welch's t-test (p < 0.01). This study shows the advantage and reliability of utilising micro-CT for firing pin impression analysis. Quantitation of the firing pin impression allows distinction between the weapons studied. With expansion to further weapons, application of this methodology could complement current analysis techniques through classification models. [ABSTRACT FROM AUTHOR]

Meaningful assessment and comparisons on the injury potentials of various types of ammunition and credible forensic reconstruction require an agreement on standard tissue simulant. Gelatine blocks are relatively inexpensive and easy to produce and they meet most of the criteria for a good terminal ballistic simulant. This research looks into the variables of preparing ballistic gelatine and their effects on penetration resistance. It was found out that consistent quality gelatine blocks are easy to make and that the variables like water temperature have a far smaller effect than previously thought. Also water acidity variances allowed by European Council directive on drinking water do not have any measurable effect. A proposed standard method for gelatine preparation is presented together with penetration function for verification of gelatine quality. [Copyright &y& Elsevier]

Our goal was to compare experimental gunshot wounds in our non-biological bone model with similarly created wounds in swine bones, and evaluate the results. The design of the synthetic (polyurethane) bone was patterned after human bone structure, with a compact outer layer covering a porous inner layer. Ordnance gelatin, as substitute bone marrow, was injected into the bone’s hollow core. To simulate the periostium, the bone was covered with a layer of latex. Then the bone was embedded in gelatin used to simulate surrounding soft tissue. For comparison, fresh swine bones were also embedded in gelatin, and fired upon under the same guidelines. All gunshots were high-speed filmed. In our experimental study, gunshot wounds to swine bones, and to our synthetic, non-biological bones were compared. The results (the comparison between the biological swine bones and the non-biological model bones) in regard to the following points are absolutely equal: the loss of velocity and energy after striking bone, bone fragmentation, bullet deformation, and the penetrating wound channel. Continuing studies with our synthetic bone model will bring about an even greater understanding of the mechanisms of “bullet–bone interaction”. For this reason, we have extended our variety of bone models to include other skeletal structures such as skull, spine, pelvis and flat bones for further gunshot experiments. [Copyright &y& Elsevier]

The efficacy of Gold/Zinc and Silver/Zinc vacuum metal deposition (VMD) protocols were assessed as stand-alone methods of fingermark enhancement on ballistic brass materials. The results demonstrate the effectiveness of VMD enhancement on a large pool of donors (n = 20), with potentially identifiable marks recovered for the majority of donors, including samples aged up to two months. Of the 20 donors a subset of six donors were selected to assess the capability of VMD enhancement on brass fired cartridge cases, from which some friction ridge detail (FRD) was recovered. Lastly, an attempt to understand which fingermark components are facilitators of VMD enhancement was made. Fingermark residue was extracted from brass tiles and fired cartridge cases before analysing chromatographically (GC-MS). Although some key components were indicated, further evaluation of all fingermark components is needed to draw firm conclusions as to the role each plays in VMD enhancement. [ABSTRACT FROM AUTHOR]

Sometimes the firearm forensic examiner is required to provide information useful to discriminate between suicide, homicide or accident, or between contradictory reconstructions of the events (like attempted murder versus accidental discharge). In such situations, knowledge of the position and orientation of the firearm at the time of firing can be of fundamental help for the reconstruction of events. To achieve these goals, the analysis of the firing impressions is very important. In this study, the cartridge cases shot with three different revolvers aiming at three different spatial orientations (vertical upwards, horizontal or vertical downwards) were studied. The depth and morphology of the firing pin impression was characterised by optical microscopy and quantified by a surface topography analysis. The orientation of the firearm significantly modified the morphology and depth of the firing pin impression: ammunition fired upwards had the deepest firing pin impression, those fired downwards had the shallowest. Such behaviour was attributed to the different geometry of the firing pin-primer cup interaction and to the different pressure exerted by the primer as the orientation of the weapon changes. Therefore, this work has shown that a suitable protocol of morphological and topographical analysis can be set up to understand if a shot by a revolver was fired holding the weapon upwards, downwards or horizontally. [ABSTRACT FROM AUTHOR]

Bullet ricochet off a surface in a shooting scene occurs in diverse conditions and affected by array of factors. Therefore ricochet analysis of a particular incident demands case by case analysis supported by the knowledge of existing subject knowledge and empirical testing. In this view, existing empirical test results on bullet ricochet experiments have become always assisted and referred by investigators during scene reconstruction and in Courts. This forensic based research was aimed to understand the ricochet behaviour and related aspects of Kalashnikov bullets (7.62mm×39mm) on 1mm sheet metal. 1mm sheet metal was selected as the target surface of the study, based on its greater possibility of existing in concurrent urban environments as vehicle bodies, electrical appliances, road signs, boundary walls, partitions, walls of mobile houses etc. The research added brand new knowledge to the firearm investigation field in general and specifically to AK shooting investigations and scene reconstruction. The ricochet angles and critical angle of 1mm sheet metal and AK bullets, relationship of different impact feathers and angle of incidences are some of the main findings of the research. The double head impact mark which produces as a result of bullet's interaction with the target and it's specific relationships with the incident angles is the other most important results of the research which has not reported so far in a bullet ricochet study. In addition to the contribution of knowledge to the field of forensic sciences in general and forensic ballistic in particular, this research further emphasises the need for case by case empirical study to understand the ricochet behaviour of different bullet and target combinations. On the other hand, this study very deeply convinced firearms investigators on the risk of applying general bullet ricochet theory on yielding and nonyielding surfaces to reconstruct all bullet ricochet incidents which would result in wrong interpretations, critical errors in shooting scene reconstruction and finally for false testimonies. [ABSTRACT FROM AUTHOR]

Abstract: When analysing blood spatters, traces often occur which regarding the collision angle, cannot be allocated to any supposed centre of origin. Drops following highly curved (ballistic) trajectories usually form these types of traces. The reconstruction of such trajectories requires knowledge of the mass, the diameter (of which approximations are known) and the velocity of the blood drops. This article provides an upper range of the velocity in relation to the diameter of the blood drops based on physical laws. This is very helpful in analysing ballistic trajectories. [Copyright &y& Elsevier]

Plastilina is often used as a ballistic witness material (BWM) behind the armour to evaluate the backface signature (BFS). Indeed, it is cheap, reusable and it keeps its deformation after being impacted. Moreover, while it aims at evaluating the performance of ballistic protections when no perforation occurs, it can be subjected to a very wide range of strain/shear rates during a ballistic impact. Therefore, there is a need to improve the knowledge about the mechanical/rheological response of such a material. This paper proposes both experimental and modelling approaches to determine the response of the specific ballistic plastilina red Weible® over a wide range of shear/strain rate. A capillary rheometry analysis with control of temperature was performed up to 8.104 s-1. The corrections of Rabinowitsch and Bagley were applied and an attempt of the analysis of Mooney was considered. From the rheology of plasticine, a two-parameters based power-law constitutive equation was deduced. An experimental drop test was carried out using a specific standard setup. A high-speed camera was used for measuring the penetration depth of a steel ball into the plastilina. A numerical simulation of the drop test was performed by taking into account the mechanical properties of the plastilina. A good correlation was observed between the experimental and numerical results in terms of indentation depth evolution. [ABSTRACT FROM AUTHOR]

The focus of this research was to examine the contribution chemical trace evidence makes to criminal justice outcomes. The aim of this work was to place the discipline of chemical trace evidence under the spotlight as there is a dearth of robust research on the impact of this discipline. In this study, data relating to the forensic examinations in a sample of 238 cases which included chemical trace evidence, was collated with data from police investigations and court processes. The findings show that chemical trace evidence is frequently used in combination with other forensic disciplines to support the progress of high-level criminal cases through the justice system. Due to characteristics of how the criminal cases in the dataset were investigated and prosecuted, in combination with the methodology applied in this study, the impact of forensic evidence on the decision to charge suspects could not be analysed quantitatively. However, the impact of forensic evidence on court outcomes in the sample of cases was analysed using methodology that considered the results of the examinations, and the ability of the evidence to provide support for the inclusion or exclusion of persons of interest. The possibility of chemical trace evidence having impact when applied in combination with other forensic disciplines was also examined. It was found that biological examination results was a significant standalone predictor of court outcomes. In contrast, chemical trace examinations did not predict court outcomes when considered as a standalone predictor but examination results of chemical trace evidence in combination with ballistics/tool marks was significantly associated with court outcomes. The findings of this research indicate that, to assess the full impact of any discipline of forensic evidence on the criminal justice system, the analysis must take into account the potential for important synergies that may exist with other forensic and non-forensic evidence. [ABSTRACT FROM AUTHOR]

Pertinent marks of fired cartridge cases such as firing pin, breech face, extractor, ejector, etc. are used for firearm identification. A non-standard semiautomatic pistol and four .22rim fire cartridges (head stamp KF) is used for known source comparison study. Two test fired cartridge cases are examined under stereomicroscope. The characteristic marks are captured by digital camera and comparative analysis of striation marks is done by using different tools available in the Microsoft word (Windows 8) of a computer system. The similarities of striation marks thus obtained are highly convincing to identify the firearm. In this paper, an effort has been made to study and compare the striation marks of two fired cartridge cases using stereomicroscope, digital camera and computer system. Comparison microscope is not used in this study. The method described in this study is simple, cost effective, transport to field study and can be equipped in a crime scene vehicle to facilitate immediate on spot examination. The findings may be highly helpful to the forensic community, law enforcement agencies and students. [ABSTRACT FROM AUTHOR]