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Shot with 9-mm bullet to the occipital bone, 9 ms after impact. After the “burst” backspatter with gushes of liquid and bone fragments, the “collapse” backspatter streams in direction of the gun as a thick microspatter spray. The inner parts of the gun are exposed to the backspatter due to the recoil process
Source publication
Molecular ballistics connects the molecular genetic analysis of biological traces with the wounding events and complex forensic traces investigated in terminal ballistics. Backspatter, which originates from a projectile hitting a biological target when blood and/or tissue is propelled back into the direction of the gun, is of particular interest; t...
Similar publications
Blank cartridge guns are prevalent especially in countries with laws restricting access to conventional firearms, and it is a common misconception that these weapons are harmless and only used as toys or for intimidation. However, although their harming potential is well-documented by numerous reports of accidents, suicides, and homicides, a system...
Citations
... To understand the phenomenon and its variability, systematic experimental research was conducted [17,18] and a simple, but reliable target model [19] was developed which allowed for generating staining inside firearm barrels as well as observing the temporary cavity [20,21] and backspatter [22]. Other models, like a Synbone® polyurethane skull, were proposed [23,24]. However, the more complex the model, the more doubtful/difficult is the reproducibility of a physical experiment [25]. ...
Biological traces inside firearm barrels were observed as a result of contact shots to the head. The present study was conducted to investigate the influence of the muzzle to target distance on staining inside the anterior and posterior part of firearm barrels. Ninety-nine shots were fired to so-called reference cubes (10% gelatine, 12 cm edge length, embedded paint-blood-pad) using three current handguns. Shot range was varied from contact to 50 cm distance. High-speed cameras recorded external backspatter. Endoscopic examination assessed visible staining along the barrel. Each two swabbings were gathered from the anterior and the posterior part of the barrel. The first swabs were submitted to quantitative PCR, the second ones to DNA-RNA-co-extraction. Thorough mechanical and chemical cleaning was performed to avoid any contamination which was controlled by negative zero swabs after each cleaning. In single shots up to 50 cm distance, minimal, but DNA-positive sporadic traces were detected inside the barrel in vicinity of the muzzle. Visible complex staining varying in extent was observed in the anterior barrel part for 10 cm or less distance in dependence of the calibre. The posterior part showed detectable traces only after close range shots (< 5 cm). Generally staining inside the barrel decreased from the muzzle to the rear end, which correlated with the yield of DNA. Some contact shots did not cause any staining in the posterior part of the barrel despite massive external backspatter. Blood-specific miRNA was primarily found where DNA was detected. This experience encourages to take a second swab for RNA analysis. The amount of nucleic acids in the barrel at varying muzzle to target distances is subject to large variations between individual shots and therefore appears not suitable for a reliable determination of the shot distance in a particular case on its own. Instead, shot range estimation should also take into account morphology and distribution of traces inside the barrel.
... It continuous with a field guide that focusses on backspatter that can be generated by bullets and ends with a look at future applications and prospects of molecular ballistics. Another study is a feasibility study [148]. Shots were fired at an anatomically correct but standardized skull replica covered with a thin layer of rubber and filled with an internally attached reservoir (with blood, acrylic paint and contrast agent) and gelatine as a brain simulant. ...
... During temporary cavitation, strong negative pressures appear resulting in entrance of air, debris, bacteria, as well as skin particles, all sucked into the wound. Collapse of the cavity is implicated in the mechanism of backspatter of blood and tissue fragments from the entrance wound towards the source of the bullet, particularly in head injuries (Karger, 2008;Kneubuehl, 2011;Euteneuer et al., 2019). ...
This article presents the various aspects of gunshot wounds, including epidemiology of firearm-related deaths, wound ballistics and forensic examination of gunshot victims. Determination of the range of fire based on the morphology of the entrance wound is discussed in detail both for bullet wounds and shotgun injuries, along with imaging studies (including postmortem computed tomography) providing valuable insight into the wound prior to autopsy. Forensic implications, namely determination of the manner of death assisted by gunshot residue analysis, are briefly examined. Finally, recent experience from mass shooting incidents is reviewed.
... The blood spatter analysis on the hands of victim can help not only to determine the location of the entrance wound, wound path trajectory and the hand utilised to discharge the firearm, but also substantiates the reconstruction about the position from which the weapon was fired in the most scientific manner in cases with controversy about manner of death. This applicability of the blood spatter analysis has already been reported earlier [29]. In this regard, analysis and documentation of blood-spatter findings on the hands is recommended before hands are tested for gunpowder residue or wrapped while transportation of the body in cases of alleged suicide by usage of firearms [30]. ...
... Authors after reviewing the literature that emphasized the enormous importance of back-spatter in criminal investigations [29][30][31], dwelled with the idea to conduct a study that is obviated of the need of the utilization of alive or slaughtered animals required to be killed for understanding the mechanism and applicability of back spatter in determination of range in firearm injuries in humans, contrasting earlier studies [24,26,28]. Search of a target material that will be invariably present as evidence over the dead body in cases of violent crimes related to firearm injuries in humans was also anticipated by authors, instead of extrapolation of the results of a study utilizing hypothetical material like blood filled sponge or reference cubes as utilised in previous studies [23,33]. ...
Background
Numerous studies have been conducted by using sophisticated methodologies for the deduction of range in cases of firearm injuries. However, the stark dearth of literature for similar purpose by just simple analysis of blood traces on items of clothing is astonishing. Purpose
This study was done to determine the relationship between range of a rifled firearm and blood traces on the clothing of victims in firearm injuries.
Methodology
Simulation experiments were performed by firing test shots in closed shooting range by using a Glock 17 pistol (9 mm luger) into pieces of clothing soaked with sheep blood. A total of 132 shots were fired. The morphologies and amount of blood spatter formed over a range varying from 5cm - 100cm (shooting angle-90°) were studied.
Results
An inverse relationship was found to exist between morphology of blood traces produced on the target and the distance of the shot fired. The misting and micro-blood spatters were recorded at a range of 5cm - 60cm. The distance from which shots were fired carried significant impact on the appearance and density of the spray and the blood spatter.
Conclusions
The results provide a scientifically determined, statistically valid and simple equation formula in the most cost effective and easy manner for the deduction of range by mere examination of clothing in cases of firearm injuries. The requirements of the sacrifice of animals, and/or extrapolation of the results to humans by conducting experiments using hypothetical targets were also obviated in this study.
... The contrast mixture used in this study comprised venous blood and an X-ray contrast agent to facilitate radiological wound channel evaluation via CT analysis as described before [16,29]. However, the wound channels produced by the blank gun shots proved to be small and mostly filled with gunshot residues (GSR), barring meaningful results from CT analysis which was hence discarded. ...
... Also, in addition to our data presented so far and taking into account the abstract nature of experiments with gelatin model setups, we believe that it may be useful and instructive to present some more quite illustrative if only anecdotal evidence of the drastic effect of and hence danger posed by blank firing guns of different kinds. Firstly, we fired the Ekol pistol and Skullfire ammunition at an empty, anatomically realistic skull model made from polyurethane (SYNBONE, Switzerland) that simulates the mechanical properties of human bone and whose forensic use has been described elsewhere [16,29]. Several shots penetrated the skull simulant that had been covered with a double layer of chamois leather as skin simulant, creating considerable defects in the model ( Supplementary Fig. 15). ...
Blank cartridge guns are prevalent especially in countries with laws restricting access to conventional firearms, and it is a common misconception that these weapons are harmless and only used as toys or for intimidation. However, although their harming potential is well-documented by numerous reports of accidents, suicides, and homicides, a systematic molecular biological investigation of traces generated by shots from blank cartridges at biological targets has not been done so far. Herein, we investigate the occurrence and analyzability of backspatter generated by shots of different types of blank cartridge guns firing different types of blank ammunition at ballistic gelatin model cubes doped with human blood and radiological contrast agent soaked into a spongious matrix and covered with three different variants of skin simulants. All skin simulants were penetrated, and backspatter was created in 100% of the shots in amounts sufficient for forensic short tandem repeat (STR) typing that resulted in the correct identification of the respective blood donor. Visible backspatter was documented on the muzzle and/or inside the barrel in all cases, and in 75% of cases also on the outer surfaces and on the shooter’s hand(s). Wound cavities were measured and ranged between 1 and 4.5 cm in depth. Discussing our findings, we provide recommendations for finding, recovering, and analyzing trace material from blank guns, and we demonstrate the considerable hazard potential of these devices, which is further emphasized by the presentation of a comprehensive overview of the pertinent literature on injuries inflicted by blank guns.
... This central object often connects the victim(s) and the perpetrator, therefore traces recovered from there may be of substantial evidential weight. In fact, backspatter traces can consolidate on basically all outer and inner surfaces of a firearm and when manifested as microspatter (droplet size < 0.5 mm diameter [36]) may even be invisible for the unaided eye but still yield DNA profiles [18,19,37,38]. Thus, when collecting evidence for crime reconstruction, all surfaces of a firearm should be carefully investigated, and all detachable parts should be disassembled and evaluated for traces as well. ...
... They also highlighted the difficulty in proper nuclease-free weapon cleaning, especially for RNA residues. Alternatively, a modified version of the doubleswab technique has also been applied frequently, with the head of one single swab moistened on one half while leaving the other half dry [20,21,37,38]. This approach increases the sample concentration on the swab but should be adapted to the amount of material found at the respective weapon. ...
... In pistols, the outer surface of the barrel, which is covered and protected by the slide, is only shortly exposed during the shooting process. This short interval of exposition was shown to temporally correlate with the backspatter trajectory so the outside of a pistol's barrel may "catch" backspatter particles which then consolidate and remain there covered by the slide until collected [37,38] ( Fig. 4). Also, the barrel outside and other inner surfaces except the barrel inside are less exposed to and affected by the physical and chemical stress caused by secondary and further shots with the same weapon that may destroy or remove trace material that had consolidated on the inner surface of the barrel after the first shot [19]. ...
Molecular ballistics combines molecular biological, forensic ballistic, and wound ballistic insights and approaches in the description, collection, objective investigation, and contextualization of the complex patterns of biological evidence that are generated by gunshots at biological targets. Setting out in 2010 with two seminal publications proving the principle that DNA from backspatter collected from inside surfaces of firearms can be retreived and successfully be analyzed, molecular ballistics covered a lot of ground until today. In this review, 10 years later, we begin with a comprehensive description and brief history of the field and lay out its intersections with other forensic disciplines like wound ballistics, forensic molecular biology, blood pattern analysis, and crime scene investigation. In an application guide section, we aim to raise consciousness to backspatter traces and the inside surfaces of firearms as sources of forensic evidence. Covering crime scene practical as well as forensic genetic aspects, we introduce operational requirements and lay out possible procedures, including forensic RNA analysis, when searching for, collecting, analyzing, and contextualizing such trace material. We discuss the intricacies and rationales of ballistic model building, employing different tissue, skin, and bone simulants and the advantages of the “triple-contrast” method in molecular ballistics and give advice on how to stage experimental shootings in molecular ballistic research. Finally, we take a look at future applications and prospects of molecular ballistics.
... In the present study, we aim to assess whether after replicated shots with different types of firearms at a realistic ballistic model of the human skull [14] a correlation of distribution of and DNA content from backspatter traces and/or the wound profile inferred from the gelatin core of the skull model with the shooting distance can be established. ...
... We employed and established an anatomically realistic ballistic skull model [14] which was used for every shooting session with a few deviations. Briefly, commercially available and anatomically correct hollow SYNBONE® skull models with rubber coating (model number 8880.G, SYNOBONE AG, Switzerland) were cleaned from the inside and doped with a tissue simulating spongy matrix soaked with the "double-contrast" mix and sealed in evacuated vacuum bags. ...
... After the radiological imaging, the skull models were photographed, and any peculiarities were noted. Afterwards, they were processed as described by Euteneuer et al. [14]. The gelatin brain simulant was extracted and serially cut into about 1-cm-thick slices perpendicular to the wound channel. ...
In molecular ballistics, where traces originating from the use of firearms against biological targets are investigated, “backspatter” traces are of particular importance. This biological material comprising blood and tissue from the victim is propelled back from the bullet entry site towards the direction of the shooter and can consolidate and persist on the inner and outer surfaces of the firearm, from where it can be collected and analyzed. Thus, a connection between the weapon and the victim can be established solely by molecular biological trace analysis. For the criminalistic investigation of gun-related crimes, the determination of the distance between the weapon and the victim can be of critical importance in reconstructing the circumstances of a crime. In this study, we investigated possible correlations between the shooting distance and the amount of backspatter in/on the used firearm. To this purpose, we employed a previously established skull model and performed shootings in triplicates from various distances up to 50 cm with two types of handguns (pistol and revolver). Backspatter was collected from various sampling locations, and DNA contents were quantified. A post-shooting wound channel evaluation was conducted by optical and radiological evaluation. The obtained DNA yields varied considerably between replicates from the same and from different distances. In contrast, apart from contact shots, no meaningful differences were observable in wound channel evaluations. In summary, no meaningful correlation between backspatter distribution and DNA yields, the shooting distance and the condition of the wound channel could be established.
... In this study, to assess the influence of shooting distance on the distribution and quantity of backspatter recoverable from inside the gun, we employed a previously devised anatomically realistic skull model with a gelatine core doped with blood and contrast agent [7] in a series of shooting experiments involving a pistol and a revolver representing the most frequently used types of firearms in gun-related homicides, with the occipital bone as the typical target region [8]. DNA yield from backspatter traces and wound profiles were investigated in relation to the shooting distance, correlated to one another and evaluated for potential patterns and limits. ...
... Shootings were conducted in triplicates per distance (0 cm, 5 cm, 10 cm, 15 cm, and 30 cm) for each weapon (Glock 19, 9 mm Luger and Smith & Wesson .38 Special CTG Model 36) employing previously devised skull models [7]. After each shot, backspatter traces were collected by double-swab technique [9] with DNA-free 4N6 FLOQ Swabs Genetics (Copan) from three surfaces of the gun (see Table 1). ...
In molecular ballistics, the molecular genetic analysis of biological material is integrated with the biophysical wounding events and trace investigations of terminal ballistics. It aims to support the objective, evidence-based reconstruction of gun-related crimes. Of central interest is the analysis of backspatter traces: biological material propelled back from the entry site of a bullet after impact on a biological target. This study is a first approach to systematically investigate possible correlations or patterns between the amount of recoverable DNA (yield) from backspatter traces found on and inside fired guns and the shooting distance. After firing shots from five distances (0, 5, 10, 15, 30 cm) with both a pistol and revolver in triplicates, no clear correlations or patterns can be observed, due to considerable variation between measurements from identical triplicates and a lack of linear relation between distance and yield, e.g. yields from even 30 cm shots will sometimes exceed those of contact shots. Wound channel evaluation was performed as well and distinct differences between contact shots and distance shots could be observed, but not between any distant shots.
Experimental data describing the uniaxial compression and relaxation of brain tissue are compared to the predictions from a rheological model developed by Yarin and Kosmerl [“Rheology of brain tissue and hydrogels: A novel hyperelastic and viscoelastic model for forensic applications,” Phys. Fluids 35, 101910 (2023)]. A qualitative agreement between the model and experiments with swine brain tissue is confirmed, and the uniformly valid values (i.e., valid in all rheometric experiments without any change) of the rheological parameters are established. These are the values of the following four parameters: G (the shear modulus), κ (the bulk modulus), α (the dimensionless degree of hyperelasticity), and θ (the viscoelastic relaxation time). In addition, the present rheological model with the established rheological parameters is incorporated into a dynamic model of bullet penetration into brain tissue after a short-range shooting, when muzzle gases and/or air fill the bullet channel leading to its widening, wave propagation, fragmentation, and backspatter of brain tissue. This problem is of significant interest in forensic science because there is an urgent need to provide physics-informed models to reconstruct and analyze crime scenes.
Penetrating combat injuries by fragments are of concern during tactical warfare. The fragments generated from the explosive devices can cause lethal penetration in various organs, including the head. The response of the head against fragment impact is unknown.
To experimentally investigate the ballistic response of an open-shape head surrogate model against fragment impact. We hypothesize that the response of the head surrogate to the impact of small fragments is different than that of larger projectiles. The ballistic response of the head surrogate was evaluated in terms of ballistic limit velocities (V50), energies (E50), energy densities (E50/A) required for the penetration, and associated failure mechanisms in various layers of the head surrogate.
The head surrogate was prepared by stacking rectangle cross-sectioned skin, skull, and brain simulants. Chisel-nosed fragment simulating projectiles (FSPs) of 1.10-g and 2.79-g were impacted on the head surrogate using a pneumatic gas gun setup.
V50 and E50/A of the 2.79-g FSP were lower by ~ 50% than the 1.10-g FSP. The skin simulant failed by the combination of shearing and elastic hole enlargement. The skull simulant failed by a conoid fracture. In penetration cases, the FSP broke the fractured conoid of the skull simulant in smaller pieces and penetrated into the brain simulant. Interestingly, for the cases of non-penetration into the brain simulant, the brain simulant was damaged due to the moving conoid of the skull simulant.
The results demonstrated that V50 and E50/A were influenced by the size of the FSP. For the investigated fragments, 15–25 J of energy was sufficient to cause various degrees of penetration into the brain simulant. All three layers of the head surrogate failed by distinguished mechanisms.
