Study of backspatter using high-speed video of experimental gunshots.

Backspatter is biological material that is ejected from the entry wound against the line of fire. This phenomenon was also observed in wound ballistic simulations using so called "reference cubes" (12 cm edge length, 10% gelatin, 4 °C, paint pad beneath the cover). High-speed video records from 102 experimental shots to these target models using full metal jacketed bullets in the calibers .32 auto, .38 special, 9 mm Luger and .357 Magnum were analyzed for chronology, morphological appearance and velocity of fluid ejection. Generally, a short tail splashing of surface material occurred when the bullet was penetrating the target. In 51 shots from distance (≥ 5 cm), regardless of caliber and shot range, a linear jet of fluid started in connection with the first collapse of the temporary cavity. The initial velocity of the jet was measured between 6 and 45 m/s. The jet was streaming on for about 60 to 100 ms with a stochastic deviation of ± 13° to the horizontal. Close range and contact shots showed earlier and faster (up to 330 m/s) backspatter depending on the cartridge and the gap between muzzle and target. Gaseous aerosol-like spray and cone-like spatter indicated an increasing influence of muzzle gases with decreasing shot range. Even under standardized experimental conditions, variations of backspatter were observed in near/contact shots

Demands on scientific studies: vitality of wounds and wound age estimation. Forensic Sci. Int 2007;165:150–154. [PubMed: 16806766

Abstract Research on vitality and wound age estimation belongs to the classic fields in forensic medicine. Despite large literature data there is still considerable demand of further research and practical transfer of knowledge and techniques to daily casework. Scientific studies must fulfil basic criteria as to appropriate methods, selection of case material, analysis of results and quality control. Nowadays, immunohistochemistry, biochemical tests and molecular biological techniques are mainly used studying questions of vitality and wound age. Investigations can be based on human tissue samples (autopsy material, vital specimens) or animal experiments. The possibilities, advantages and disadvantages of these study designs are described. Indispensable is the use of appropriate control groups or control samples and a sufficient case number which permits statistical analysis. Main strategy is to minimize variations due to methods and investigators as the unavoidable biological variation of vitality processes and wound repair is large enough.

Review Drug Testing and Analysis Ricin poisoning and forensic toxicology †

Ricin is one of the most fascinating poisons due to its high toxicity: as little as 500 µg can kill an adult. It gained fame by its use in the so-called 'umbrella murder' to kill the Bulgarian dissident Georgi Markov in 1978. Ricin also became known as a potential bio-terror agent to which people could be exposed through the air, food, or water. The origin, biochemistry, toxicity, and analytical procedures for the determination of ricin are summarized. The homicide of Markov is described as well as recent cases of criminal ricin use