C. Schyma

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 bullets 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.

Persistence of biological traces in gun barrels-an approach to an experimental model

Traces of backspatter in gun barrels after homicidal or suicidal contact shots may be a valuable source of forensic evidence. Yet, a systematic investigation of the persistence and durability of DNA from biological traces in gun barrels is lacking. Our aim was to generate a realistic model to emulate blood and tissue spatters in gun barrels generated by contact gunshots at biological targets and to analyse the persistence and typability of DNA recovered from such stains. Herein, we devise and evaluate three different models for the emulation of backspatter from contact shots: a gelatine-based model with embedded blood bags, a model based on a spongious matrix soaked with blood and covered with a thin plastic membrane and a head model consisting of an acrylic half sphere filled with ballistic gelatine and with blood bags attached to the sphere under a 3-mm silicone layer. The sampling procedure for all three models: a first shot was fired with several types of guns at each model construction and subsequently a second shot was fired at a backstop. Blood samples were collected after each shot by probing the inner surface of the front and rear end of the respective gun barrel with a sterile swab. DNA was then extracted and quantified and up to 20 different short tandem repeat (STR) systems were amplified to generate DNA profiles. Although DNA quantity and STR typing results were heterogenous between the models, all models succeeded in delivering full STR profiles even after more than one shot. We conclude that biological traces in gun barrels are robust and accessible to forensic analysis and that systematic examination of the inside of gun barrels may be advisable for forensic casework.

Persistence of biological traces in gun barrels after fatal contact shots.

In the majority of cases suicidal shots are put to the head. Typically the guns muzzle is held against the head. The aim of the present prospective study was to investigate whether victim DNA could reliably be recovered from the inside of the barrels of firearms that were used in 20 cases of homicidal or suicidal close contact shots. Additionally, it was investigated whether such biological traces were eliminated by subsequent firing. After autopsy sterile swabs were used to collect samples from the anterior part of the barrel thereby avoiding the muzzle. In some cases prior endoscopic inspection had revealed traces of blood and soft tissue in the barrel. For 16 cases, another swab was used to also collect sample from the posterior part of the barrel entering from its rear end. Then one shot was fired through the weapon using the same ammunition as in the suicidal shot and the sampling procedure was repeated. DNA was extracted using a magnetic beads based protocol, quantified, and STR-systems were amplified using several commercially available multiplex-STR-PCR-kits. For samples taken after the first shot DNA-analysis yielded STR profiles eligible for reliable individualization in 17 of 20 cases. After a second shot had been fired 8 or more STR systems were amplified successfully in 14 of 20 barrels.

Colour contrast in ballistic gelatine.

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 x 19 Action-5, 9 mm x 19 Quick Defense 1, 5.56 mm x 45 Styx Action) was realized on 10% gelatine blocks at 4 degrees C temperature. Three blocks were marked with acryl paint on the front, three blocks were shot native. The blocks were cut in slices of 1cm thickness and optically scanned. The evaluation was performed according to Facklers 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 1cm 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.

Suicide by head explosion: Unusual blast wave injuries to the cardiovascular system

A 57-year-old employee in a military scientific institute was found acephalous in a supine position in an anteroom to the bunker. On the walls was abundant spattering of blood and tissue, concentrated above shoulder height. A mobile ignition device stood on the control desk. The complete destruction of the head down to the cervical spine suggested that the explosive charge (RDX) detonated in his mouth. The hands were virtually uninjured. The pressure effect in vessels caused numerous tears to the wall of the carotid arteries and the left vertebral artery, a tear-off of the left carotid artery of the aortic arch, and a 2.5-cm long crack of the thoracic aorta with 540-ml blood in the pericardial sac and a shredded window-like disruption of the left aortic valve cusp. The autopsy also showed an infraction of the sternum from the inside, and a contusion of the superior lobes of both lungs. The trace pattern on the right arm suggested suicide. A bone fragment of the mandible penetrated the right biceps muscle as a secondary projectile.

Extended suicide by use of a chain saw

Injuries caused by chain saws are mostly seen due to accidents. Suicides by chain saws are rare, but some cases have already been described. We present the case of homicide on a child by a chain saw followed by the suicide of his father. For the homicide and the suicide chain saws of different sizes were used. Fatal injuries in the homicide and suicide were located on the neck. Cause of death in both cases was fatal haemorrhage with blood aspiration respectively decapitation. Normally, in suicide by use of chain saws individuals suffering from schizophrenia, major depression and alcohol or drug dependence are concerned. In the presented case, the background was a litigation of a divorced couple for child custody.

DNA-PCR ANALYSIS OF BLOODSTAINS SAMPLED BY THE POLYVINYL-ALCOHOL METHOD

Among the usual techniques of sampling gunshot residues (GSR), the polyvinyl-alcohol method (PVAL) includes the advantage of embedding all particles, foreign bodies and stains on the surface of the shooters hand in exact and reproducible topographic localization. The aim of the present study on ten persons killed by firearms was to check the possibility of DNA-PCR typing of blood traces embedded in the PVAL gloves in a second step following GSR analysis. The results of these examinations verify that the PVAL technique does not include factors that inhibit successful PCR typing. Thus the PVAL method can be recommended as a combination technique to secure and preserve inorganic and biological traces at the same time.

The MEN frangible: study of a new bullet in gelatin. Metallwerk Elisenhütte Nassau.

Experimental gunshots were made with 9 x 19 mm (9-mm Luger) Frangible ammunition using skin, gelatin, and bones as targets. Direct gunshots penetrated 50 cm into gelatin blocks without mushrooming or fragmentation. Skull bone was easily perforated. Head models were penetrated by the bullets, which broke down to myriad fragments within or outside the head. Gunshots through windshields and steel plates led to dangerous bullet fragmentation with a high risk of injury. Gunshots perforating tibias produced comminuted fractures. In all soft tissues, except the direct gunshots into gelatin, high-resolution radiography revealed many metallic fragments along the bullet path. Clinical radiography can show the larger copper fragments, but the explosion-like distribution of metallic foreign bodies in soft tissue is a serious surgical problem.

Gardner–Diamond syndrome: a rare differential diagnosis of child abuse

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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.