Search

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 BALISTIKA 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 BALISTIKA 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 BALISTIKA 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.

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, a NIST/ATF joint project entitled National Ballistics Imaging Comparison (NBIC) was initialized in 2008. The NBIC project aims to establish a National Traceability and Quality System for ballistics identifications in crime laboratories within the National Integrated Ballistics Information Network (NIBIN) of the U.S. NIST Standard Reference Material (SRM) 2460 bullets and 2461 cartridge cases are used as reference standards. 19 ballistics examiners from 13 U.S. crime laboratories participated in this project. They each performed 24 periodic image acquisitions and correlations of the SRM bullets and cartridge cases over the course of a year, but one examiner only participated in Phase 1 tests of SRM cartridge case. The correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed Quality System and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard.

Existing works on pellet dispersion ballistics are confined to some data-based models derived from statistical analysis of observed patterns on targets but the underlying process causing the dispersion lacks due attention. The present article delves into the relatively unexplored areas of dispersion phenomena, and attempts to develop a theoretical model for general application. The radial velocity distribution of pellets has been worked out by probing into the physical process of dispersion based on transfer of momentum from undispersed shot mass to dispersed pellets. The ratio 2u/v0 (u = root mean square (r.m.s.) radial velocity and v0 = muzzle velocity of the pellets) is found to be fairly constant for a fixed gun-ammunition combination and has been suitably designated as 'Dispersion Index' (DI) characterising its dispersion capability. The present model adequately accounts for pellet distribution on targets and it appears that 'Effective Shot Dispersion' (ESD) as introduced by Mattoo and Nabar [ESD = [(4/N0)sigma Ri2]1/2, where N(0) is the total number of pellets and Ri is the radial distance of the i-th pellet from centre of pattern], gives a faithful numerical measure of overall dispersion at a given distance. A relationship between ESD and firing distance, incorporating the effects of air resistance and gravity has been worked out, which reveals that DI controls the dispersion at a given distance. For small distances (less than 20 m) the relation reduces to a linear one, as already observed empirically and looks like ESD = E0+DI x firing distance, E0 being a parameter dependent on gun and ammunition. The present model, unlike earlier ones, is versatile enough to explain the natures of the dependence of dispersion on firing distance as well as on gun-ammunition parameters, which are essential for a faithful reconstruction of a crime scene. The model has been tested with such experimental data as are available and reasonable agreement is observed.

This paper reports on a study of the characteristics of weapons with delayed blowback systems and the physical phenomenon of that type of closure in establishing appreciable traces on the empty cases.

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 PM(2.5) 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): 58.9 μg/m(3); barium (Ba): 6.9 μg/m(3); antimony (Sb): 7.3 μg/m(3)). The mean value of the airborne in this room during 6 monitored days was Pb: 23.1 μg/m(3); Ba: 2.2 μg/m(3); Sb: 1.5 μg/m(3). 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.

The Liberator is a firearm that can be manufactured from its blueprints, using a 3D-printer. This weapon made of nineteen pieces - eighteen in printed plastic and one metallic nail - raises questions such as its ability to fire a round, its wounding potential and the traces produced by its discharge. In particular, knowledge must be gained to infer that a 3D-printed handgun was used, reconstruct the shooting event involving such handgun, and gather information related to the type of 3D-printed handgun used. This study focused on the traces that could orientate forensic investigations when the use of a 3D-printed Liberator is suspected. In a first step, the Liberator was investigated to study its behaviour during the discharge and characterize traces produced by the discharge. To fulfil this goal, some Liberators were printed and assembled. Six Liberators fired a round. The discharge of the weapons was done under specific conditions allowing to collect ballistics data and traces produced by the shooting. The results showed that the barrel tended to break between the ignition of the primer and the moment the projectile exited the muzzle. The speed of the projectiles reached 140m/s when the barrel broke, while it was about 170m/s when barrel remained intact. The trajectory of the projectiles was sometimes disrupted, and the projectile tumbled on itself. It was thus very difficult to characterize the trajectory. The cavity wound caused by the fastest bullet was typical of a handgun wound firing a FMJ projectile (penetration of 21cm in ballistics soap). On the other hand, the cavity caused by the slowest bullet was more representative of a splinter wound (penetration of 14cm in ballistics soap). The study of gunshot residues collected on adhesive targets showed the presence of unburnt particles and small perforations caused by polymer pieces that concentrated around the entry holes.

The ballistic resistance of a combined soft tissue simulant was studied, consisting of gelatine as a simulant for human muscle tissue and tanned cowhide (leather) as a simulant for human skin. The simulant was manufactured by applying cowhide to liquid ballistic gelatine, as the gelatine solidified in its mould. Combining a skin and muscle tissue simulant in this adhered way opens the possibility to produce purpose-built proxies for human body parts in ballistic studies or for forensic shooting incident reconstructions. Ballistic resistance of adhered cowhide - (bonded) to solidifying ballistic gelatine - was compared to that of the same material applied on gelatine blocks in loose condition. Ballistic resistance of tanned cowhide was found to be more consistent in adhered condition. This enhanced consistency is a benefit, increasing reproducibility of results in ballistic studies. Additionally, two ways to assess ballistic resistance of a skin simulant were described and compared. Logistic regression, from a number of measured velocities and associated (non)perforations is recommended for testing ballistic resistance.

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 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 x 19 mm, .40 S&W, and .45 ACP) and four different bullet types. Synbone® spheres (polyurethane bone proxies) were used for close range (30 cm) 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

This paper details the review of the gunshot residue (GSR) evidence relating to a 2002 murder involving the discharge of a pistol where the Prosecution used the GSR findings together with voice identification evidence and obtained a conviction in the case of R v Dwaine George. Mr George was subsequently represented by Cardiff University Law School's Innocence Project who made representations to the Criminal Cases Review Commission (CCRC) based on issues relating to the GSR evidence. The CCRC commissioned their own expert review and based on these findings referred the conviction to the Court of Appeal stating that in their opinion the weight of the GSR evidence was not appropriately conveyed to the jury at the original Trial and there should have been a warning relating to the limited significance that could be attached to the evidence. The Court of Appeal concluded that had the jury been aware of the full extent of the potential alternative sources of GSR in the case and the limited number of particles found on a jacket related to Mr George then this would have affected the decision of the Trial jury. The appeal was allowed and the convictions were quashed.

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.

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.

The velocity of a projectile is of crucial importance to calculate its kinetic energy. The study was performed to investigate if a measurement of the velocity profile of a bullet in gelatine was feasible using high-speed video. More than 50 records captured with a SA-X2 Photron camera at 40,000 fps (40k) and 10 μs exposure time were analysed frame by frame. A measurement accuracy of one pixel could be realised. Records of free flying bullets with known velocity served as a control. In further experimental shots from distance the "12 cm reference cube" was used as target model. 18 full metal jacketed bullets and 20 deforming bullets in forensically relevant calibres were fired. In addition 11 expanding bullets were studied with a close-up setting of the camera and 81,000 fps (81k) at 2.5 μs exposure time. A quasi-constant deceleration of the FMJ bullets in gelatine with a relative loss of velocity of 8.4% (.32 auto) and 13.2% (9 mm Luger) was observed. Expanding bullets showed a much higher deceleration and a relative loss of about 56% for the copper hollow point bullet and 73% for the .32 auto Gold Dot. The targeted analysis of the .32 auto Gold Dot based on 81k videos revealed an abrupt drop of the bullet velocity within the first 75 μs, the time needed for full expansion. The deformation of the Action-4 (9 mm Luger) was completely achieved within the first 2 cm of gelatine. After the deformation of the bullet the final deceleration was approximately constant. This could be demonstrated successfully by separating the deformation process experimentally from the final deceleration of the deformed bullet.

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.

Trajectory deflections of 5.56 NATO and 7.62×39mm rifle bullets, fired through 7.5, 15 and 22.5cm of gelatine, were studied. The magnitude of the deflections from the bullets' original trajectories after perforation are related to the length and the profile of the (wound) channels through gelatine. After 7.5cm of penetration depth, deflection was less than 1°. With the longer channel lengths, bullet instability set in and subsequently, deflection was much larger. Deflection was highest with fragmented 5.56 NATO bullets after perforating 22.5cm of gelatine. The data from this study can be used to assess the degree of bullet deflection in trajectory reconstructions after incidents where human bodies were perforated with rifle bullets of the respective calibres and cartridge types.

When a person is shot, they are generally wearing clothing which will be damaged by the perforation of the bullet. There are relatively few reports of such textile damage in the literature and the effect of blood on the textile damage observed is not reported. The appearance of textile damage caused by bullet impacts is further compounded by the diverse nature of (i) fabrics used in apparel and (ii) ammunition types. In this work, the effect of blood on textile damage due to ballistic impact was investigated by the development of a specimen that incorporated blood. The specimens were impacted with two types of pistol ammunition that are commonly available (i) 9 mm Luger HP (8.03 g; Federal Premium® Law Enforcement; jacketed hollow-point) and (ii) .357 Magnum (10.24 g; Express® Pistol and Revolver; Remington, R357M3, flat-nose soft-point). The resulting textile damage was compared to that in specimens without a bleeding layer. The interaction of blood with textile damage caused by a bullet-impact affected the appearance of the textile damage and resulted in the dispersion of the bullet wipe. These results are important in the content of evidence examined by a textile damage assessor compared to what might be seen in a typical re-creation event in a laboratory. The use of a bleeding layer in textile damage investigations due to ballistic impact resulted in a more realistic scenario.

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.

The ricochet behaviour of AK bullets (7,62 × 39 mm), one of the prominently reported bullet type in recent shooting incidents worldwide, has been examined on a range of different wooden surfaces in this study. The critical angles of AK bullets for teak, Jack wood, mahogany and pine were reported with close values ranging from 9.9 to 13.3- degrees, suggestive of being a valuable reference that can be used during AK bullet ricochet-related shooting investigations with similar conditions. The study also highlighted a significant phenomenon against the existing understanding on the wood hardness and the critical angles of bullets. The widths of the AK bullet wipe marks generated on the wood surfaces were highly consistent, regardless of impact angle, allowing an effective approximation of bullet caliber. Bullet tunnelling effect were also observed with pinewood samples in this study. The study also further highlights the great variability of bullet ricochet phenomena and the challenging nature of using the theoretical and experimental results relates to wood ricochet studies for shooting reconstructions.

We study the transient indirect effect of a rifle bullet on bone in the gelatin-bone composite target experimentally and computationally. The process of a 56 type 7.62-mm rifle bullet penetrating the composite target has been simulated using numerical method. The experiment provided the criteria for verifying the correctness of the numerical model. We have obtained tomographic data of bone by CT scans, and also defined the bone as different layers by the gray scale to simulate its heterogeneity. The computed results are in good agreement with the experimental data. Effects of the impact velocity and bone location on damage caused to the composite target have also been studied. The numerical results imply the follows: When the velocity of bullet increases, the stress on bone also increases with the earlier pressure peak; When the bone is located in a certain distance from the trajectory, it will not be fractured, although it is affected by the stress wave.

Post-mortem CT scanning (PMCT) has been introduced at several forensic medical institutions many years ago and has proved to be a useful tool. 3D models of bones, skin, internal organs and bullet paths can rapidly be generated using post-processing software. These 3D models reflect the individual physiognomics and can be used to create whole-body 3D virtual animations. In such way, virtual reconstructions of the probable ante-mortem postures of victims can be constructed and contribute to understand the sequence of events. This procedure is demonstrated in two victims of gunshot injuries. Case #1 was a man showing three perforating gunshot wounds, who died due to the injuries of the incident. Whole-body PMCT was performed and 3D reconstructions of bones, relevant internal organs and bullet paths were generated. Using 3ds Max software and a human anatomy 3D model, a virtual animated body was built and probable ante-mortem postures visualized. Case #2 was a man presenting three perforating gunshot wounds, who survived the incident: one in the left arm and two in the thorax. Only CT scans of the thorax, abdomen and the injured arm were provided by the hospital. Therefore, a whole-body 3D model reflecting the anatomical proportions of the patient was made combining the actual bones of the victim with those obtained from the human anatomy 3D model. The resulted 3D model was used for the animation process. Several probable postures were also visualized in this case. It has be shown that in Case #1 the lesions and the bullet path were not consistent with an upright standing position; instead, the victim was slightly bent forward, i.e. he was sitting or running when he was shot. In Case #2, one of the bullets could have passed through the arm and continued into the thorax. In conclusion, specialized 3D modelling and animation techniques allow for the reconstruction of ante-mortem postures based on both PMCT and clinical CT.

The location of a gunshot entrance wound as well as the wound path trajectory are the main findings that help to determine the position from which a weapon was fired and thus distinguish firearm suicides from homicides and accidents. We present a case of a 28-year old man, who was found dead in his car. Because of an unusual position of the firearm, which was clamped into the steering wheel, and an unclear entrance/exit wound, an autopsy was performed. The deceased showed typical signs of a contact shotgun wound to the head with an entrance wound in the right temporal region and an exit wound in the midface. With the help of gunpowder attachments and a muzzle imprint at the entrance site, a wound channel from the right lower posterior part of the temporal region to the left anterior part of the mid-facial region could be reconstructed. The stellate wound in the midface was assessed as an atypical exit wound. The cause of death was a contact shotgun shot to the right temple with a consequent central regulatory failure due to extensive brain injury. The manner of death was concluded to be a suicide.

Forensic pathologists who autopsy the victims of gun violence are often called upon to answer questions in both criminal and civil proceedings about the relative position of the shooter and the victim. In this case report of an officer-involved shooting incident, the statement of the police officer appeared to be in direct contradiction to the statements of other eyewitnesses, the evidence at the scene, and the final resting position of the decedent's body. Trajectory analysis of two gunshot wound pathways (only one of which was instantaneously incapacitating) was performed to assess the veracity of the officer’s statement and forensic animation was used to create a court exhibit. A discussion of the current peer-reviewed literature is included.

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.

Using the best-fit ellipse method, single bullet impacts in thin sheet metal were assessed to investigate the accuracy of impact angle estimation. When a bullet passes through a metal panel, the yielding nature of metal causes changes to the metal surface and the resultant hole. This deformation of the metal complicates the assessment of single impacts using the ellipse method. Determining the correct impact angle may not be obvious and results in considerable errors between the known and calculated angle. To determine if the calculated angle varies in any particular way to the known angle, impacts were created on metal panels using six different types of 9 mm ammunition and seven angles from 90° to 14°. Impact angles, determined using the ellipse method, were compared with known firing angles and the error pattern assessed. The results show an error pattern with a significant quadratic relationship for three ammunition types, with the error pattern for the remaining three ammunitions not explained by a quadratic formula and requiring further study. Results suggest that single bullet impacts for a given type of ammunition with a quadratic error pattern, can be assessed with accuracy due to a more consistent behavior. This characteristic pattern of error requires further study but is a promising step for determining an accurate impact angle and bullet path from a single impact point in a metal surface.

In this study we have evaluated the detectability of lead deriving from Gunshot Residues (GSR) on human bone using colorimetric techniques as well as the possible interferences of decalcification on the stainability of these particles. 22 well preserved cadavers were divided into two groups: group A enlisted 11 victims deceased because of gunshot injuries (bones and soft tissues sampled in correspondence of the entry wound of the bullet)- and group B, comprehending 11 victims deceased for natural causes (specimens sampled from intact skin areas). All the samples, after decalcification processes for bone specimens with a 14 % HCl solution, underwent standard histological procedures and were stained with hematoxylin and eosin (H&E), sodium rhodizonate (Na-R) and acidified sodium rhodizonate (Na-R-HCl 5 %). Two additional slides of soft tissues for each group were pre-treated with HCl 14 % before being stained with likewise staining. In group A, 10 samples out of 11 resulted to be negative to Na-R and Na-R-HCl 5% techniques while all the corresponding soft tissues resulted to be positive for the same staining. Additional soft tissue slides processed with 14 % HCl solution were negative in 10 cases out of 11. No sample in group B showed positivity to the staining procedures neither with nor without pre-treatment with 14 % HCl. The search for GSR residues on human bone is therefore not executable with Na-R and Na-R-HCl 5 % techniques since the essential decalcifying procedure modifies the stainability of the residues therefore adulterating the results.

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.

Ballistic gelatin is the simulant of the human body during field tests in forensics and other related fields, due to its physical and mechanical similarities to human trunk and organs. Since the ballistic gelatin used in present has important issues to overcome, an alternative approach is the use of gelatin-polymer composites, where a key factor is the insertion of biocompatible materials, which replicate accurately the human tissues. In order to be able to obtain an improved material in terms of mechanical performances by an easy industrial-scale technology, before the verification of the ballistic parameters by shooting in agreement with military standards, one of the best and cheapest solutions is to perform a thorough check of their rheological properties, in standard conditions.

When considering the impact and value of gunshot residues (GSR) as forensic trace evidence, the likelihood of a suspect producing a positive GSR analysis result without having direct exposure to a firearm is a major consideration. Therefore, the random prevalence of GSR and 'GSR-like' residues in the wider population is a highly pertinent question when considering the probative value of such evidence. The random prevalence of GSR in two Australian jurisdictions - Victoria and South Australia - was assessed through the collection and analysis of GSR samples obtained from randomly selected members of the public. Volunteers were asked to declare any firearms use, hobbies or potential firearms exposure before allowing their hands to be sampled using aluminium GSR sample stubs coated in adhesive tape. A total of 289 samples, 120 from Victoria and 169 from South Australia were collected and analysed using scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDS). Across all samples, three 'characteristic' three-component Pb/Ba/Sb particles were detected from a single subject in South Australia, corresponding to an overall prevalence of 0.3%. Two-component 'consistent' particles were more prevalent, with Pb/Sb particles being the most frequently occurring, in 8% of samples, and in South Australia only. A number of samples, approximately 7%, showed populations of single element particles of Pb, Ba and Sb, which has the potential to generate a false positive for GSR if using a bulk analysis technique such as NAA or AAS. The prevalence of GSR or 'GSR like' particles in this study matches closely with similar surveys conducted in other jurisdictions. Such surveys are a useful foundation for the creation of a probabilistic method for the assessment of GSR evidence.

Reconstruction of brain injuries is a basic task of forensic neuropathology. For better understanding of the wound ballistics of gunshot injuries to the brain caused by low-velocity firearms (E(o)550 J), we reviewed the respective contributions of: (1) biomechanical reconstruction by postmortem imaging techniques, (2) biometry of the extent of very early microscopic tissue destruction, and (3) microscopic studies on the type and extent of early microscopic reactions around the permanent missile track.A selected case material of 47 victims of lethal gunshot wounding to the brain was studied. (1) Computed tomography (CT) and magnetic resonance imaging (MRI) techniques were compared with macroscopic findings in 17 cases. (2) Morphometric evaluation of the zones of cellular and axonal destruction around the permanent track was performed in 20 cases (survival time:90 min). (3) Microscopic studies of the emigration of leukocytes and macrophages plus axonal expression of beta-amyloid precursor protein (beta-APP) were conducted in 10 cases (survival time:90 min).(1) Imaging procedures provided valuable information on entrance and exit wounds, the missile track and secondary changes. (2) Biometry revealed a destruction zone of ca. 3.6 cm around the permanent track corresponding to the "temporary cavity". (3) Microscopic studies of reactive changes demonstrated axonal injury at sites remote from the permanent cavity that could explain the very early respiratory arrest following low-velocity gunshot injury.

Experiments were undertaken in order to explore the potential for gunshot residue (GSR) particles to undergo tertiary transfer, and to be deposited on individuals in the vicinity of a firearm discharge. Samples were taken from hands following a series of test-firings. SEM–EDX with automated detection and analysis software was used to determine the presence of GSR on these samples. As many as 22 particles were found to have undergone tertiary transfer via a series of handshakes following a firearm discharge. In one run, a particle measuring 49.19μm was recovered from a tertiary transfer recipient. Significant numbers of particles were also recovered from bystanders, with as many as 36 being detected on a sample taken from an individual who was in the proximity of a firearm discharge. The implications of these observations for forensic investigations are considered. In particular, the need to prevent unwanted transfer during the collection phase is highlighted, and the importance of acknowledging the possibility of secondary and tertiary transfers when reconstructing firearms incidents is also stressed. Experimental studies offer a means of improving our understanding of the dynamics of GSR transfer and deposition, and assisting the forensic reconstruction of firearms incidents.

Chemical evaluation of gunshot residues (GSR) produced by non-toxic lead-free ammunition (NTA) has been a challenge to forensic analyses. Our group developed some luminescent markers specific to the detection of GSR. Here, we evaluated the performance of selected markers in experiments that mimic forensic context and/or routines in which luminescent characteristics would be very useful. We evaluated the influence of markers' addition on the bullet's speed, the rate of shot failure (i.e., when the cartridge case is not fully ejected and/or a new ammunition is not automatically replaced in the gun chamber) as a function of marker percentage, the possibility of collecting luminescent gunshot residue (LGSR) in unconventional locations (e.g. the shooters' nostrils), the LGSR lifetime after hand washing, the transfer of LGSR to objects handled by the shooter, and the dispersion of LGSR at the crime scene and on simulated victims. It was observed that high amounts of marker (10 wt%) cause high rates of failure on pistols, as well as a substantial decrease in bullet speed. However, the use of 2 wt% of marker minimizes these effects and allows LGSR detection, collection and analysis. Moreover, in all conditions tested, markers showed high performance and provided important information for forensic analyses. For instance, the LGSR particles were found on the floor, ranging from 0 to 9.4 m away from the shooter, on the door panel and seats after a car shooting experiment, and were found easily on a pig leg used to simulate a victim. When a selective tagging was done, it was possible to obtain positive or negative correlation between the victim and shooter. Additionally LGSR possesses a fairly long lifetime (9 h) and good resistance to hand washing (up to 16 washes).

Although air weapons are considerably lower in power than other firearms, there is increasing concern that serious injuries can result from their misuse. The present study was therefore carried out to improve understanding of the terminal ballistic behaviour of air rifle pellets. Pellets were fired into ballistic gel under a variety of conditions. The pellets penetrated further than anticipated from their low cross-sectional density, and Bloom number was not necessarily a good guide to gel behaviour. Pellet penetration into the gel decreased with increasing gel concentration, and appeared to be linear at higher concentrations. Pointed pellets penetrated up to 50% further than rounded pellets. Power and range affect penetration, but other factors are also important, and power alone is not a simple guide to potential penetration. Test firings were also carried out firing pellets into ballistic gel that contained sections of animal bone. Computed tomography (CT) and visual observation were employed to record the interactions. CT scanning showed potential as a tool for examining pellet damage. The bone appeared to be undamaged, but the pellets were severely deformed on impact. If the pellet strikes the bone at an angle, less energy is absorbed by the impact and the pellet fragments may ricochet and cause further damage in the gel. A tentative model is proposed for estimating the energy absorbed by the impact.

Gelatine is a reliable tissue simulant in wound ballistic experiments. The projectile penetrating the gelatine transfers energy and causes radial cracks according to the temporary cavity. Thus the crack length is a function of the energy spent in the medium. In practice the fissures are poorly contrasted for which reason an enhancement of contrast was searched. A series of six shoots with expanding bullets (9 mm × 19 Action-5, 9 mm × 19 Quick Defense 1, 5.56 mm × 45 Styx Action) was realized on 10% gelatine blocks at 4 °C temperature. Three blocks were marked with acryl paint on the front, three blocks were shot native. The blocks were cut in slices of 1 cm thickness and optically scanned. The evaluation was performed according to Fackler's wound profile, the total crack length method and the polygon method. The paint was soaked into the block by the collapse of the temporary cavity and transported with diminishing intensity to the end of the trajectory. Colour contrast was successfully realized in all the shots which made easier to measure the length of the fissures. The comparison of the shots with and without paint gave a better reproducibility of measures with colour contrast. Using paint the energy transfer began earlier so that the curve of the wound profile was shifted by 1 cm to the entry which is explicated by the paint pad put on the block. The maximum crack lengths did not significantly differ with and without paint. All evaluation methods profited from colour contrast but the total crack length method the most of all. Further experiments showed that colour contrast is also successful in 20% gelatine and is not dependent of the type of projectile.

Blank firing weapons are designed only for discharging blank ammunition cartridges. Because they are cost-effective, are easily accessible and can be modified to live firearms plus their unclear legal situation in Turkish Law makes them very popular in Turkey. 2004 through 2008, a total of 1115 modified blank weapons were seized in Turkey. Blank firing weapons are easily modified by owners, making them suitable for discharging live firearm ammunition or modified blank ammunitions. Two common methods are used for modification of blank weapons. After the modification, these weapons can discharge the live ammunition. However, due to compositional durability problems with these types of weapons; the main trend is to use the modified blank ammunitions rather than live firearm ammunition fired from modified blank firing weapons. In this study, two types of modified blank weapons and two types of modified blank cartridges were tested on three different target models. Each of the models' shooting side was coated with 1.3+/-2 mm thickness chrome tanned cowhide as a skin simulant. The first model was only coated with skin simulant. The second model was coated with skin simulant and 100% cotton police shirt. The third model was coated with skin simulant and jean denim. After the literature evaluation four high risky anatomic locations (the neck area; the eyes; the thorax area and inguinal area) were pointed out for the steel and lead projectiles are discharged from the modified blank weapons especially in close range (0-50 cm). The target models were designed for these anatomic locations. For the target models six Transparent Ballistic Candle blocks (TCB) were prepared and divided into two test groups. The first group tests were performed with lead projectiles and second group with steel projectile. The shortest penetration depth (lead projectile: 4.358 cm; steel projectile 8.032 cm) was recorded in the skin simulant and jean denim coated block for both groups. In both groups, the longest penetration depth (lead projectile: 6.434 cm; steel projectile 8.608 cm) was recorded in the only skin simulant coated block. And the penetration depth of skin simulant and 100% cotton police shirt coated model was 5.870 cm for lead projectile; 8.440 cm for steel projectile. According to penetration results, national and international legislations and production standards should be re-evaluated in order to prevent the modification of blank weapons and ammunitions. There are three methods for preventing modification of blank weapons: completely closed barrel structure; intersected restrain pieces application; eccentric barrel structure.

In today's law enforcement community, one of the most vital tools an officer can possess is personal body armor. However, a recent Department of Justice investigation has raised important questions regarding the protection actually afforded officers through the use of personal body armor, and the current test methods used to assess the armor. Test results show that most Zylon-containing vests showed deformations in excess of the 0101.04 Standard's 44 mm backface signature limit. Such increased deformation can lead to serious injuries, including backface signature injuries, which have occurred in the field. Although the vest is successful in containing the round, it is not effectively dissipating the energy enough to prevent large amounts of vest deformation at the area of impact. Therefore, open, penetrating wounds occur even though the bullet did not penetrate the vest. The objective of the current study was to further define the backface signature injury through the use of case studies and laboratory experiments. Following the case study investigation, backface signature testing was conducted using a clay medium based on the NIJ 0101.04 Standard. The final component of this research involved the use of post-mortem human specimens (PMHS) for further investigation of the backface signature injury. Although the underlying cause of backface signature injuries is unknown, energy density is likely to play a role in the mechanism. Energy density (E/a) is defined as the energy per unit area and has been previously used in less lethal skin penetration research. Further research into the underlying causes of backface signature injuries is necessary. In addition to armor testing, the study of law enforcement personnel who have been shot while wearing soft body armor is also a valuable tool for determining the effectiveness of certification standards. Finally, it is important for medical personnel to recognize the backface signature injury and document this as a type of injury separate from blunt trauma or penetrating trauma behind armor injuries. Detailed knowledge of the injury, including the depth of the wound, would be beneficial to the scientific community.

Background In cases of severe decomposition or skeletonization of a corpse after cerebral gun shot injury it is difficult to exactly reconstruct the bullet path in the brain. However, in case of murder or homicide this might become necessary to answer forensic questions such as the ability to move or other actions of the victim. Materials and methods Therefore a method in terms of three dimensional reconstruction technique was developed by fusing computed tomography scans (CT) of the original skull and magnetic resonance images (MRI) of a normal brain of adequate size. Hereby five cases were investigated. Results In three cases an excellent concordance between the reconstructed bullet trajectory and the autopsy reports was achieved. In one case the original brain was not available for CT-scanning due to previous autopsy. However, the findings were in line with the pathology report. In one case there was a difference of about 1–2 cm between the original autopsy description and the reconstructed bullet path. This was due to only a part of the skull being available for image reconstruction. Conclusion The findings suggest that this method can successfully be applied to adequately reconstruct bullet paths in cases of completely skeletonized skulls, but should carefully be used in cases of incomplete skulls.

Various methods for calculating the amount of kinetic energy dissipated by a bullet into ballistic gelatine have been suggested in literature. These methods were compared using the results of thirteen 9 mm × 19 mm pistol and five 7.62 mm × 39 mm rifle bullets shot into 10% ballistic gelatine. The Wound Profile Method gave the highest correlation, 0.89, with the measured amounts of dissipated kinetic energy. The Fissure surface area and total crack length method gained 0.51 and 0.52, respectively. The experimental results were also compared with those from pig tests with the same bullet types. Using the z-test at 95% level of confidence no difference between impact velocity normalized bullet decelerations could be determined for the 9 mm bullet used. The same test showed significant difference for 7.62 mm bullets. That, however, can be considered to be the result of the bullet's tendency to tumble in non-homogenous living tissue causing significant dispersion of observed deceleration values. The results add further evidence supporting the validity of 10% gelatine at +4 °C as wound ballistic tissue simulant. The study also introduces the use of an elastic “shroud” to hold the gelatine in place, to some extent reduce the effects of asymmetric expansion of the gelatine and to simulate the expansion suppression effect of surrounding tissues.

In a suicidal shot to the temple two roundish zones of powder soot blackening were found above the entrance wound. The paired zones of powder soot blackening were caused by two gas outlets located on the upper side of the muzzle end of the weapon used (converted blank cartridge pistol of make Rhöner). The conclusions that can be drawn from this particular soot pattern with regard to the type of the weapon, the muzzle-to-target distance, the direction of fire and the way of holding the weapon are discussed.

Ballistic imaging databases allow law enforcement to link recovered cartridge cases to other crime scenes and to firearms. The success of these databases has led many to propose that all firearms in circulation be entered into a reference ballistic image database (RBID). To assess the performance of an RBID, we fired 4200 cartridge cases from 600 9mm Para Sig Sauer model P226 series pistols. Each pistol fired two Remington cartridges, one of which was imaged in the RBID, and five additional cartridges, consisting of Federal, Speer, Winchester, Wolf, and CCI brands. Randomly selected samples from the second series of Remington cartridge cases and from the five additional brands were then correlated against the RBID. Of the 32 cartridges of the same make correlated against the RBID, 72% ranked in the top 10 positions. Likewise, of the 160 cartridges of the five different brands correlated against the database, 21% ranked in the top 10 positions. Generally, the ranking position increased as the size of the RBID increased. We obtained similar results when we expanded the RBID to include firearms with the same class characteristics for breech face marks, firing pin impressions, and extractor marks. The results of our six queries against the RBID indicate that a reference ballistics image database of new guns is currently fraught with too many difficulties to be an effective and efficient law enforcement tool.

Currently, optical devices, such as microscopes and CCD cameras, are utilized for identification of bullets and tool marks in the field of forensic science. While these optical methods are easily manageable and effective, they are under great influence of illumination condition. In other words, appearances of striations through these optical devices have possibility to be changed by lighting condition. Besides these appearance-based approaches, we can utilize three dimensional (3D) geometric data of tool marks that are free from lighting condition. In this study, we focused on 3D geometric data of landmark impressions on fired bullets for identification. We obtained the 3D surface data of tool marks by a confocal microscope and reconstructed virtual impressions on a PC monitor from the geometric data. Furthermore, the 3D data are exploited to numerical matching of two surface shapes. We also visualized the difference of two shapes. In order to do this, two surface models are aligned automatically. In this process, pairings of correspondent points on both surfaces are determined. Distance analysis between these pairs leads to a shape comparison. Since comparison results are visualized, they are intuitive and easily perceptive.