Bullet wipe on the uppermost textile layer of gunshot entrance sites: may it be absent due to pre-existing blood staining?

Abstract

Most gunshot entrance sites on human victims are localized in clothed body regions. Except for the use of lead-free ammunition, a positive color reaction of the sodium rhodizonate test indicates a primary target hit by the bullet. Any lead residue pattern in the area around the entrance hole allows approximate conclusions as to the firing distance in close and intermediate range shots, whereas the presence of a bullet wipe denotes an entrance site. A criminal case gave rise to an experimental study to clarify whether a blood-soaked garment being shot at as a primary target may lack a bullet wipe around the entrance hole. Distant-range shots were fired with a semi-automatic pistol (Heckler & Koch, Mod. USP Compact, cal. 9-mm Luger) using cartridges with jacketed round-nose bullets and a Sinoxid primer containing lead styphnate. In fabrics saturated with fluid blood, a wide area around the bullet entrance was densely covered with rhodizonate-positive microparticles simulating gunshot residues (GSR) from a close-range shot. In shots to fabrics oversaturated with blood, a typical bullet wipe was lacking, whereas lead-containing particles were spotted in the periphery. The results are discussed with respect to the aberrant appearance of bullet entrance sites in blood-soaked fabrics.