The deceleration of full metal jacket bullets in compact target models - A new approach.

The wounding potential of a projectile depends on its kinetic energy. The aim of the study was to investigate the deceleration of non-deforming full metal jacket handgun bullets (FMJ) in gelatine blocks of increasing length. The temporary cavity (TC) was visualized using a SA-X2 Photron camera. 126 test shots in 9 mm nominal calibre were fired under strict temperature control conditions (4°C) at small gelatine blocks ranging from 2 to 12 cm in length. The deposited energy was calculated based on the loss of bullet velocity through high-speed video analysis. The length of the TC was measured, when the TC reached its maximum height. The volume of the TC was approximated by a cylinder. Regression analysis showed a linear correlation between the length of the bullet path and the energy transfer. The constant deceleration of the FMJ bullets in gelatine up to 12 cm bullet path was confirmed across various brands and velocity ranges (270-450 m/s). Higher impact velocities correlated with increased loss of energy in the target medium. The shape of the bullet tip influenced the characteristic of deceleration. The volume of the tubular temporary cavity, derived from high-speed video records, was found to be proportional to the energy transferred. The proposed approach might be a valuable tool in advancing wound ballistics research.

The influence of impact velocity on bullet trajectory deflection through ballistic gelatine.

This paper presents the results of a study on bullet trajectory deflection, for 9 mm Luger Full Metal Jacket Round Nose (FMJ-RN) bullets fired through 23-24 cm of ballistic gelatine. The bullets were fired at different velocities. Impact velocity, energy transfer and bullet trajectory deflection after gelatine perforation were measured and calculated. As was expected, energy transfer to the gelatine blocks generally increased with increasing impact velocity, indicating an altering bullet/gelatine interaction with altering velocity. This alteration did not result in a discernible alteration of bullet trajectory deflection. Deflection angles fell between 5.7° and 7.4° for 136 of the 140 fired shots, with four outliers below 5.7°.

The influence of muzzle gas on the temporary cavity.

Shot range, the muzzle-target distance, is a crucial parameter for forensic reconstruction of deaths by firearms. In a large number of cases, especially suicides, the forensic pathologist is confronted with contact or near-contact shots, where muzzle gases play an additional role. This study was conducted to systematically investigate the influence of muzzle gases on the temporary cavity (TC). A total of 72 shots were fired using full metal-jacketed bullets in four forensically relevant calibres from 10-, 5-, 3-, 2- and 1-cm distance and in close contact. Target model was the so-called reference cube (10% gelatine at 4 °C) with 12-cm edge length. The TC was recorded using high-speed video (HSV). Cross-sectional analysis was performed by cutting the blocks to 1-cm slices, which were evaluated by applying the polygon method. The TC of shots from 10 and 5 cm distance had a tubular form. This aspect changed depending on the cartridge with decreasing distance (≤ 3 cm) into a pear-like form, which was typical for contact shots. The cumulated heights of the TC increased with decreasing distance below 3 cm. Contact shots approximately doubled the extension of the TC compared with exclusive energy transfer. Whereas HSV documented an increasingly asymmetric profile with ballooning at the entry side, cross-sectional analysis of cracks in gelatine resulted in convex graphs with only slight asymmetry for contact shots. Additional damage in gelatine was detected for 3-cm distance or less in calibre .357 Magnum and ≤ 2 cm for .32 auto, .38 special and 9mm Luger. The increasing influence of muzzle gas pressure is detectable with decreasing shot range below 3 cm.

The deceleration of bullets in gelatine - A study based on high-speed video 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.

The influence of the counterfort while ballistic testing using gelatine blocks.

In wound ballistic research, gelatine blocks of various dimensions are used depending on the simulated anatomical region. When relatively small blocks are used as substitute for a head, problems with regard to the expansion of the gelatine block could arise. The study was conducted to analyse the influence of the material the gelatine block is placed upon. Thirty-six shots were performed on 12 cm gelatine cubes doped with thin foil bags containing acrylic paint. Eighteen blocks each were placed on a rigid table or on a synthetic sponge of 5 cm height. Deforming bullets with different kinetic energies were fired from distance and recorded by a high-speed video camera. Subsequently, the gelatine cubes were cut into 1 cm thick slices which were scanned using a flatbed scanner. Cracks in the gelatine were analysed by measuring the longest crack, Fackler's wound profile and the polygon (perimeter and area) outlining the ends of the cracks. The energy dissipated ranged from 153 to 707 J. For moderate energy transfer, no significant influence of the sustaining material was discerned. With increasing dissipated energy, the sponge was compressed correspondingly, and the cracks were longer than in gelatine blocks which had been placed on a table. High-speed video revealed a loss of symmetry and a flattened inferior margin of the temporary cavity with energies superior to approx. Two hundred Joules when the blocks were placed on a rigid platform. However, 12 cm gelatine cubes showed material limits by a non-linear response when more than 400 J were dissipated for both rigid and elastic sustainment. In conclusion, the smaller the gelatine blocks and the greater the energy transfers, the more important it is to take into account the counterfort of the sustaining material.

Staining in firearm barrels after experimental contact shots.

After contact shots to the head biological traces inside firearm barrels can be found. This study was conducted to simulate and to evaluate such staining. Five current handguns of four inch barrel length in the calibre .22 long rifle, 7.65mm Browning, 9mm Luger and .38 special were used to perform 24 contact shots on silicone coated, gelatine filled box models using the triple contrast method. The staining was documented by endoscopy and swabs gathered from both ends of the barrel were analysed by quantitative PCR. With the exception of the .22 revolver, all firearms showed distinct staining which decreased from the muzzle to the rear end of the barrel. The pattern was varied, showing droplets, elongated forms or stripes. In 14 of 24 shots, staining reached the chamber. The staining results were comparable to real suicide cases.

Visualization of the powder pocket and its influence on staining in firearm barrels in experimental contact shots.

The powder pocket or soot cavity is a morphologic characteristic of a close contact shot. In a research project concerning staining inside the barrel, the influence of the powder pocket on these traces was investigated.According to the 'triple contrast method', thin pads containing a mixture of acrylic paint, radiocontrast agent and blood were glued on plastic boxes which were coated with a 3-4-mm-thick silicone layer. The containers filled with 10 % ballistic gelatine, were stored for at least 60 h at 4 °C. Thirty-three contact shots were realized using different pistols and 22 lr, .32 auto, .38 special and 9-mm Luger with different barrel length using subsonic, non-deforming ammunition.The documentation comprised endoscopy, high speed video and computer tomography (CT) of the target models. Using image analysis, the ballooning of the silicone coat was studied (lateral view projection).High-speed video confirmed the actual comprehension of the behaviour of muzzle gases in contact shots. The powder cavity rises in about 1.5 to 2 ms, preceding the maximum of the temporary cavity, and the powder pocket's collapse takes 2.5 to 3 ms.The size of the silicone dome increased with decreasing barrel length. Comparing semi-automatic pistols of 4 in. barrel length in the calibres, .32 auto and 9-mm Luger, there were no significant differences of the powder pocket size. Material transport was observed, against and perpendicularly to the shooting direction. CT showed undermining and gas inclusions inside the powder pocket. A correlation between amount and pattern of the staining inside the barrel and the volume of the powder pocket was not observed.

Post-mortem CT and MR brain imaging of putrefied corpses.

INTRODUCTION: Putrefaction of the brain is a challenge to a forensic pathologist because it may lead to considerable organ alterations and restrict documenting reliable autopsy findings. OBJECTIVES: This study aims to present a new and systematic evaluation of possible benefits of post-mortem MR Neuroimaging (1.5 Tesla, sequences: T1w, T2w) in putrefied corpses in comparison to PMCT and autopsy. METHODS: A post-mortem MRI brain examination was conducted on 35 adult, putrefied corpses after performing a whole body CT scan prior to a forensic autopsy. Imaging data and autopsy findings were compared with regard to brain symmetry, gray and white matter junction, ventricular system, basal ganglia, cerebellum, brain stem, and possible pathological findings. RESULTS: At autopsy, a reliable assessment of the anatomical brain structures was often restricted. MR imaging offered an assessment of the anatomical brain structures, even at advanced stages of putrefaction. In two cases, MR imaging revealed pathological findings that were detectable neither by CT scans nor at autopsy. CONCLUSIONS: Post-mortem MR imaging of putrefied brains offers the possibility to assess brain morphology, even if the brain is liquefied. Post-mortem MR imaging of the brain should be considered if the assessment of a putrefied brain is crucial to the evaluation of a forensic autopsy case.

Body weight estimation based on postmortem CT data--validation of a multiplication factor.

Postmortem computed tomography (pmCT) is increasingly applied in forensic medicine as a documentation and diagnostic tool. The present study investigated if pmCT data can be used to estimate the corpse weight. In 50 forensic cases, pmCT examinations were performed prior to autopsy and the pmCT data were used to determine the body volume using an automated segmentation tool. PmCT was performed within 48 h postmortem. The body weights assessed prior to autopsy and the body volumes assessed using the pmCT data were used to calculate individual multiplication factors. The mean postmortem multiplication factor for the study cases was 1.07 g/ml. Using this factor, the body weight may be estimated retrospectively when necessary. Severe artifact causing foreign bodies within the corpses limit the use of pmCT data for body weight estimations.

Bloodless aortic dissection.

"Bloodless aortic dissection" is a rare cause of sudden death due to an aortic dissection without intimal tears and with no blood present within the dissected aortic wall. The first case was described in 1993. Death was considered to be caused by acute myocardial ischemia from dissection involving the left coronary artery. Further cases have been described where death was thought to originate from increasing hypertension during progressive extension of the dissection followed by a sudden irritation of the subendothelially localized conduction system of the heart. The presented case involves a rapidly fatal aortic dissection in a 64 year old man without any intimal tears and no blood in the dissected aortic wall, although the dissection involved the entire aorta. Death was considered due to myocardial ischemia since the dissection had reached the aortic root and the origins of the coronary arteries.

Combined radio-colour contrast in the examination of ballistic head models.

The conventional analysis of ballistic gelatine is performed by transillumination and scanning of 1-cm-thick slices. Previous research demonstrated the advantages of colour and radio contrast in gelatine for computed tomography (CT). The aim of this study was to determine whether this method could be applied to head models in order to facilitate their examination. Four head models of about 14 cm in diameter were prepared from two acryl hollow spheres and two polypropylene hollow spheres. Acryl paint was mixed with barium meal and sealed in a thin foil bag which was attached to the gelatine-filled sphere which was covered with about 3-mm-thick silicone. The head models were shot at using 9 mm × 19 expanding bullets from 4 m distance. The models were examined via multislice CT. The gelatine core was removed; the bullet track was photographed and cut into consecutive slices which were scanned optically. CT images were processed with Corel Photo-Paint. Optical and radiological images were analysed using the AxioVision software. The disruption of the gelatine within the head model was visualised by extensive distribution of paint up to the end of the finest cracks and fissures and along the whole bullet track. CT imaging with excellent radio contrast in the gelatine cracks caused by the temporary cavity allowed for multiplanar reconstruction. We conclude that the combination of colour contrast in gelatine with contrast material-enhanced CT facilitates accurate measurements in ballistic head models.

Kinking of a coronary artery as a rare complication in mitral valve replacement.

We present the case of a 70-year old woman who had elective mitral and aortic valve surgery. She underwent surgery without complications for about 4h until 4 pm. Approx. 3h after surgery her condition deteriorated. 1500ml of blood were collected in the chest drainage until 11 pm. An emergency thoracotomy in the patient's bed showed a ventricular rupture. Death occurred around 11:30 pm. At autopsy, the implants of the biological mitral and aortic valves were found to be sewn tightly. There was no vascular injury and no unusual bleedings to the mediastinum. In the left ventricular wall, a rupture of 1cm and a surrounding fresh myocardial infarction area of 10cm×6cm was noted. Preparation of the coronary arteries showed moderate coronary atherossclerosis without stenosis or clots. The left circumflex coronary artery (LCX) showed a sharp, obviously stenosing kink which had been caused by the mitral valve surgery. Exsanguination due to ventricular rupture following myocardial infarction caused by implant-related "kinking" of a coronary artery, was found to be the cause of death.

Histological examination of the carotid bifurcation in case of violence against the neck.

The carotid body and carotid sinus are localized in the area of the carotid bifurcation and respond to pressure fluctuations in the arterial blood vessel system. In case of irritation or stimulation, nervous impulses can reflexively increase the ventilation or slow down the heart rate and blood pressure, respectively. The external stimulation of the carotid sinus by neck compression with subsequent bradycardia or asystolia, especially in pre-existing heart-disease, is discussed controversially in the literature. Histological examination of the tissue of the carotid bifurcation, particularly with regard to haemorrhage as an indication of tissue trauma, should be carried out in terms of simple and easy feasibility in routine diagnostics. In 20 cases of violence against the neck and additionally 82 cases of a control group without neck trauma and variable causes of death, the carotid bifurcations were examined histologically. Only in one case of violence against the neck haemorrhage was found, which suggested a direct trauma to the tissue of the carotid bifurcation, but evidence of lethal cardiac reflex was not found in any case.

Evaluation of the temporary cavity in ordnance gelatine.

Gelatine is a recognized tissue simulant in wound ballistic research. The deceleration of a bullet causes a temporary cavity which provokes radial fissures by stretching the gelatine. The evaluation of gelatine destruction was performed with very different methods yet, widely known are the wound profile by Fackler and the total crack length (TCL) method. Aims of the presented experimental study were to cover a wide range of kinetic bullet energy, to gather all destruction associated parameters and to correlate them to energy dissipation. According to recommendations of the Technical Guideline Commission of the German police and to Fackler, a 10% solution of Gelita Ballistic 3 gelatine was moulded in 20 cm × 20 cm × 50 cm dimensioned blocks. In the front of the blocks a 2 mm thin and 8 cm × 8 cm film bag containing about 8 g pasty acryl paint was integrated. The blocks were cooled to 4°C and were shot from a distance of 5m. The bullet's velocity was measured in front of the target. The expanding bullets Silvertip(®) (Winchester) und First Defense(®) (Magtech) were used. Varying calibres, loads and barrel lengths bullet velocities from 250 to 686 m/s were achieved while kinetic energy was spread from 71 up to 1450 J. All projectiles were captured in gelatine and had mushroomed, as expected. The blocks were freshly cut into 1cm-slices which were optically scanned. The evaluation was performed with AxioVision (Zeiss) software and in each slice the following parameters were taken: longest fissure radius, wound profile (addition of the two longest fissures), sum of the three longest cracks, TCL, perimeter and area of the polygon created by linking the fissure ends. All analyzed parameters - either crack length based methods (wound profile and the TCL) or destruction area based methods (polygon method) - showed a strong dependence of the gelatine destruction and the energy dissipated. This regularity could be approximated by linear function (correlation coefficient>0.95). The gelatine destruction seems to allow a conclusion on the amount of dissipated energy.

Extended suicide using an atypical stud gun.

Suicides with stud guns are uncommon, but are well documented in the literature. On rare occasions, stud guns are also used as a homicide weapon. This case report describes an extended suicide in which a husband killed his wife and their two dogs, which lived on the property. The husband then committed suicide with a shot from the stud gun into his skull. He was a 70-year-old pensioner, a retired butcher, who was found by his son. He was lying in a supine position on a carpet in the living room, with the stud gun stuck in his skull. During autopsy, high concentrations of an antihistamine were found in the blood of each corpse; this drug is used as a soporific. In contrast to the literature, which mainly describes powder deposits due to the use of conventional stud guns, in this case a stud gun was used in which the expanding gases and powder escaped together with the central bolt at the front of the device; powder drains were not involved. Detailed findings of the autopsy are given with reference to this type of stud gun.

Two simultaneous suicidal gunshots to the head with robbed police guns.

The suicidal infliction of two gunshot wounds to the head represents a critical issue for medicolegal investigation. In principle, simultaneous infliction with two firearms or third parties' involvement, i.e. two consecutive gunshots, have to be considered. We report for the first time on a case of suicidal infliction of two simultaneous gunshots to the head (oral, temporal) with Action 4 expanding ammunition. A male had robbed two service guns and committed suicide thereafter under the influence of high-dose alcohol and cocaine. Interestingly, Action 4 ammunition had been used, leading to an uncommon gunshot wound morphology and extensive backspatter. At the scene, these findings caused confusion; moreover, the number of gunshot wounds was unclear, until autopsy revealed two gunshot wounds to the head, which had obviously been inflicted simultaneously. Expanding ammunition like QD-PEP and Action 4, used by several German federal state police forces, can cause an atypical gunshot wound morphology, most probably due to its peculiar deformation behaviour. Investigators should be careful when interpreting gunshot wound morphology at the scene after usage of such expanding ammunition. With regard to reconstruction in cases of two gunshot wounds to the head and two guns at the scene, two simultaneous gunshots should be taken into consideration.

[Homicide by burning]. / Tötung durch Verbrennen.

Compared to the total number of deaths by heat (burning, scalding), homicides by the direct effect of thermal energy (setting the victim on fire, pouring hot liquids over them) are rare; accordingly this subject is seldom dealt with in forensic and criminological literature. From our own autopsy material three cases are presented describing some peculiarities of homicide by heat. Sometimes additional findings (e.g., residual traces of gagging or tying) primarily point in the direction of homicide.

The accelerated polyvinyl-alcohol method for GSR collection--PVAL 2.0.

The polyvinyl-alcohol collection method (PVAL) is used in forensic practice to gather topographical information about gunshot residues (GSR) from the hands to decide if the subject has made use of firearms. The results allow a distinction between suicide and homicide. The only inconvenience of PVAL was that the procedure took about 60 min because three layers of liquid PVAL had to be applied and dried. Therefore, the collection method was only applied to corpses. The improved and accelerated PVAL 2.0 uses a sandwich technique. Cotton gauze for stabilization is moistened with a 10% PVAL solution. A solid film of PVAL (Solublon) is spread on the cotton mesh. The gauze is then modeled to the hand and dried with a hair dryer. After removing the cotton gauze, the traces are embedded in the water-soluble PVAL. The procedure does not take more than 15 min. The results demonstrate the qualities and advantages of PVAL: topographical distribution of GSR, highest gain of GSR, sampling of all other traces like blood, backspatter etc., and humidity does not reduce the gain. In addition, with the new PVAL 2.0 dislocation of GSR or contamination are excluded. PVAL 2.0 can also be applied on live suspects.

[Dangers of blank firearms--risk of injury and expert assessment]. / Gefährdung durch Schreckschusswaffen--Verletzungsgefahren und Nachweismöglichkeiten.

Starters' pistols have a wounding potential which strongly depends on the shot range and the combination of weapon and ammunition. The detrimental effect consists of five aspects: gas pressure, particles, thermal effect, chemical irritation and shooting noise. Fatal injuries are caused by contact shots in the head, neck or chest. Shots from less than 5 cm distance can lead to loss of the eye. Particles work as small projectiles at distances of less than 50 cm and cause powder tattooing, concerning the eye however severe cornea injuries are possible. The thermal effect can be observed with shooting distances of up to 30 cm. The chemical irritation depends on the kind of irritant and the exposure of the victim. The acoustic trauma leads in some cases to irreversible lesions of the inner ear, depending on the distance and the position of the victim to the weapon. To provide evidence of shooting, the polyvinyl-alcohol method (PVAL), adhesive films and the examination of clothing are recommended. For the shot range, determination imaging procedures (microfocus X-ray, infrared optics etc.) and analytic methods like X-ray fluorescence (EDX) are used. A reconstruction of injury cases is performed with gelatine models (Fackler system) used in wound ballistics.