Gunshots through laminated glass: expelled compounded fragments as a function of bullet type.

In the frame of an experimental setting, the formation of round-shaped compounded glass fragments on the exit site after gunshots through a windshield was examined. For that purpose, a 9 × 19 mm pistol (HK P30) and two different cartridges containing (a) a full metal jacketed round-nosed projectile and (b) a deformation projectile were used. On the basis of 52 gunshots, the morphology, impact angles and terminal ballistics of occurring compounded glass fragments were examined. The results showed that the compounded glass fragments' morphology allowed for the differentiation of two used projectiles. Fragments were able to cause round-shaped defects in a single cotton layer (T-shirt) with subsequent penetration of up to 2.4 cm into ballistic gelatin (10%, 4 °C). As a function of the projectile type, the compounded glass fragments showed different reproducible impact angles that differed notably from the known conical pattern of expelled glass fragments after bullet penetration. These findings might help to explain the atypical morphology of gunshot wounds with laminated glass as an intermediate target and prevent possible misinterpretations when reconstructing the sequence of events.

Feasibility of an accelerated PVAL method for the collection of GSR and biological traces.

The polyvinyl alcohol method (PVAL) is known as an effective technique to thoroughly collect traces of gunshot residue (GSR) from different surfaces, e.g., from hands or gunshot wounds. Despite obvious advantages over other methods using adhesive tapes, PVAL is still not widely accepted and applied in routine case work due to a required acquisition time of at least 15 to 20 min for a single shooting hand. In this study, the feasibility of a modified procedure taking 6 to 8 min per sample is tested within the frame of an experimental setting including (1) the collection of GSR from experimental gunshots with a semi-automatic pistol and lead-containing primer ammunition and (2) a simple experimental setting involving dry and moist artificial blood traces. In a third step, samples of four gun-associated suicide cases and one attempted suicide case were taken and analyzed. Furthermore, an exemplary implementation into a work flow of modern instrumental techniques of GSR analysis is presented.