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Since decades, 10% gelatine is used to visualize and estimate the energy transfer of projectiles. The study performed investigates the correlation of the temporary cavity (TC) recorded by high-speed video (HSV) and the cracks in gelatine slices. A total of 36 shots were performed from distance using form-stable bullets (FMJ), 12 using deforming bullets (HP) in the calibres .32 auto, .38 special and 9 mm Luger. The target models were prepared according to Fackler’s standard as 10% gelatine cubes with 12 cm edge length doped with a paint pad beneath the front cover (“reference cube”). Scaled images of the TC were recorded with 40.000 fps. The cubes were cut into 1-cm-thick gelatine cross sections, which were scanned. The evaluation of the destruction (cracks) was performed by the mean of image analysis measuring the longest crack, the wound profile according to Fackler and applying the polygon method. The height of the TC was measured each cm along the bullet path. The energy deposited ranged between 54 and 269 J. FMJ caused tubular, HP provoked pear-like TC. The tubular aspect was consistent with the quasi-constant deceleration of FMJ; however, the pear-like TC did not metrically represent the deceleration of HP. The profiles of destruction parameters were convex for both projectile types and did not match the profile of bullet deceleration. The maximum of TC stretching observed in HSV did not coincide with maximum gelatine destruction (crack lengths). The total energy transfer correlated with all considered destruction parameters in their sum; however, the cross-sectional parameters did not reflect the energy transfer per centimetre bullet path. The sum of the TC’s heights correlated with the energy deposited, but differently for FMJ and HP. Obviously, the 12-cm reference cube reflects the energy transfer by a bullet as a whole.

Three-dimensional (3D) measurement techniques are gaining importance in many areas. The latest developments brought more cost-effective, user-friendly, and faster technologies onto the market. Which 3D techniques are suitable in the field of forensic medicine and what are their advantages and disadvantages? This wide-ranging study evaluated and validated various 3D measurement techniques for the forensic requirements. High-tech methods as well as low-budget systems have been tested and compared in terms of accuracy, ease of use, expenditure of time, mobility, cost, necessary knowhow, and their limitations. Within this study, various commercial measuring systems of the different techniques were tested. Based on the first results, one measuring system was selected for each technique, which appeared to be the most suitable for the forensic application or is already established in forensic medicine. A body of a deceased, a face and an injury of a living person, and a shoe sole were recorded by 11 people with different professions and previous knowledge using the selected systems. The results were assessed and the personal experiences were evaluated using a questionnaire. In addition, precision investigations were carried out using test objects. The study shows that the hand-held scanner and photogrammetry are very suitable for the 3D documentation of forensic medical findings. Their moderate acquisition costs and easy operation could lead to more frequent application in forensic medicine in the future. For special applications, the stripe-light scanner still has its justification due to its high precision, the flexible application area, and the high reliability. The results show that, thanks to the technological advances, the 3D measurement technology will have more and more impact on the routine of the forensic medical examination.

Sudden cardiac death (SCD) represents a considerable percentage of cardiovascular deaths worldwide. The most frequent pathological substrate of SCD is atherosclerotic coronary artery disease (CAD). The other, less common, pathologies which can cause SCD include cardiomyopathies, congenital diseases (including abnormal anatomy), and arrhythmias such as channelopathies, many of which are genetically determined. Autopsies of SCD victims are generally performed by forensic pathologists. In some cases, a third person responsibility could be invoked. While CAD diagnosis at post-mortem examination is not a major challenge for the forensic pathologist, the other rarer diseases may be. In such instances, referral of the hearts to specialized centers with recognized expertise is recommended, and this is particularly important in cases of SCDs of young people. Moreover, in order to avoid the frequent overdiagnosis of a pathological heart, an expert opinion should be sought for even in the presence of a morphologically normal heart. In cases where retention of the heart is not feasible, it is essential to provide an extensive photographic documentation, with the indication of the sampling sites for histological examination. However, some practical aspects, as the criteria for case selection in routine forensic practice are missing. In this paper, we present the recommendations for heart retention for a second expert opinion and the alternative of documentation and sampling for cases where retention is not possible.

Contact shots to the head often leave behind biological traces inside firearm barrels, a phenomenon of great forensic interest. Until now, the visualization and preservation of these traces presented a significant challenge, lacking a reliable method. This study addresses this gap by searching for a suitable method to extract the traces within a casting. Using alginate or gelatine as suitable materials, the results were hampered by serious adhesion issues and their extraction out of the firearm barrel was impeded. Finally, the combination of 11% gelatine with 1% alginate, introduced into the barrel around a ‘central spine’, succeeded to consistently produce replicable castings. Experimental contact shots displayed a distinct staining gradient from the muzzle to the rear of the barrel, as revealed through endoscopy and proved in the macroscopic casting. The technique proved effective for various common handgun barrels and successfully preserved blood and gunshot residue (GSR) patterns within the barrel. This method offers the dual benefits of visually mapping staining patterns and securing localized samples for targeted molecular genetic analysis in forensic investigations.

Background Suicidal gunshot wounds that are caused by ammunition fired from a 9-mm Luger pistol, with direct contact between the gun muzzle and the victim’s head, present a serious injury pattern even with full metal jacket bullets. Wound ballistic experiments were performed to clarify whether muzzle gases from the firearm have an additional wounding potential. Methods Fifteen head models were prepared as follows: an acryl sphere measuring 14 cm in diameter was completely covered with a layer of silicon that was 3 mm thick. These spheres were filled with 10% gelatine. At 4°C, these models were fired at with a 9-mm Luger pistol, loaded with Quick Defense 1 expanding bullets. Five shots were fired with direct muzzle contact, one shot was fired from a distance of 10 cm, four shots were fired from a distance of 2 m, and five shots were fired from a distance of 4 m. Results Each projectile penetrated the model; all but one projectile deformed regularly. Each acryl sphere shattered into comminuted pieces but was held together by the silicon cover. The gelatine filling was then cut into slices 1 cm thick, and each slice was optically scanned. An evaluation was performed following both Fackler’s Wound Profile method and the polygon procedure method. The pattern of gelatine disruption did not differ in shots from intermediate ranges, but the amount of gelatine destruction was always more extended in the case of muzzle contact shots. Depending on the section of the bullet path, crack lengths were 31% to 133% longer in contact shots. The first centimetre and the second half of the bullet path showed the greatest increase. Conclusion The experimental findings prove the wounding capacity of muzzle gases.

Vertebrate scavenging on human remains is occasionally observed at indoor forensic scenes, especially when pets have access to the body and their deceased owners were socially distanced. Pets feeding on corpses have implications for the forensic investigation, e.g. for trauma analysis and the assessment of the cause of death, the estimation of the postmortem interval (PMI), or the recovery of the complete set of remains. Documentation of potential scavenging in forensic practice is tenuous and needs to be improved in order to be able to use the information for future casework. Investigators need to be aware of the alterations pets can cause to human remains and how these affect further analyses. Following a combined literature review for cat and canine scavenging, we present seven new cases from Switzerland with cat and/or dog involvement. We then created a flowchart guide for a systematic collection of data to use at indoor forensic scenes of suspected scavenging. Our literature review revealed the challenge in discriminating between scavenging by domestic cats and dogs, based on the appearance of the lesions alone. Furthermore, the information that is often routinely collected in indoor fatalities with potential scavenging activity is not sufficient to perform this separation. To provide a practical basis for cat and canine scavenging and its differentiation, we summarise strategies and present a flowchart to use in forensic casework of suspected indoor scavenging.

•Incident sites and associated evidenciary findings are documented by means of 3D techniques.•Photogrammetry, optical surface and terrestrial laser scanning as well as CT are used.•3D reconstruction demonstrates run over accidents even in the absence of clear skeletal trauma.•Morphometric reconstruction is a valuable tool for interdisciplinary analysis of traffic accidents. In traffic accidents, the differentiation of run-over and other injuries is crucial because questions about the origin of fatal injuries often arise. It is sometimes difficult for forensic pathologists to answer them due to the superimposition of injuries or competing, potentially fatal findings. Therefore, using morphometric three-dimensional (3D) reconstructions offers new perspectives based on an interdisciplinary evaluation of all findings and traces. The morphometric 3D reconstruction includes the allocation of patterned injuries or transferred material, the determination of the origin of injuries as well as the reconstruction of the incident. The generated 3D models of persons, clothes, vehicles, incident sites and relevant objects resulting from forensic imaging, photogrammetry, 3D structured-light and laser scanning are included, as are all detected traces and damages. Three case studies are presented to illustrate the possibilities and results of morphometric 3D reconstruction. Run-over accidents have received less attention than the topic of pedestrian, bicycle and motorbike accident analysis for which there is a large body of literature. Our goal is to add to the understanding of run-over accidents using morphometric reconstruction in order to improve their analysis in the future. The possibilities of morphometric reconstructions by means of 3D techniques in run-over accidents are wide-ranging and can provide new, unexpected and significant insights.

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.

•We sampled 5580 blow flies at six locations around the federal city of Switzerland, Bern, by means of baited traps.•Lucilia sericata was the most frequent species from total 16 species found.•Species richness was highest in the forest but most specimens were found at the urban locations.•Indicator species were found for seasons and the forest location.•Six blow fly species were found additionally on 12 human bodies in the sampling period. To assess the species composition of necrophagous blow flies (Diptera: Calliphoridae) in the area around the federal city of Switzerland, Bern, sampling with baited bottle traps was performed over the course of 34 weeks in 2014. Six locations ranging from urban to forest habitats were sampled weekly or rather biweekly in the winter period. 5580 individuals belonging to 16 species were identified with Lucilia sericata as the most dominant and frequent species, followed by Calliphora vicina. While most individuals were found in the urban habitats, species richness was highest in the forest. Species richness and Chao–Shen entropy estimator peaked in most locations in the summer. In winter only two species were documented (C. vicina, Calliphora vomitoria). The species Lucilia illustris was found to be an indicator species for summer and autumn, while C. vomitoria was found to be an indicator species for the forest location. Entomological cases of the same time period conducted in the Institute of Forensic Medicine Bern were included to compare the species composition. Six blow fly species were found on human bodies which are in line with the monitoring. Of these, L. sericata, C. vicina and Protophormia terraenovae were the most frequent.

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.