Contact or distance shot? The morphological appearance of the permanent cavity by shots with semi-jacketed bullets
Presentation - Jun 21, 2016
Sterzik Vera, Kneubuehl Beat P, Glardon Matthieu, Riva Fabiano, Bohnert Michael
Introduction. On a late Sunday evening, an animal hunt took place in a cornfield. The setting was unusual in several ways: First because of the late daytime and fading daylight. Second because just one male person was deployed to scare up animals instead of several people. And third the man did not wear any warning clothes. After one shot with a long gun the man was found deadly injured. The hunter claimed he meant to shoot an animal. Because of the circumstances, a homicide investigation was initiated. The body showed a penetrating gunshot wound to the upper left thorax. Next to the entry wound a shaped structure could have been a muzzle impact. Underneath the entry wound inside the wound channel there were small particles of grey material. Infrared photography of the clothes revealed dark particles around the bullet hole that looked like gunshot residue.
To differentiate whether a fatal bullet wound is the result of a contact or distance shot is a common challenge in forensic casework. There are several criteria pointing towards a contact shot like muzzle impact and soot cave. However, findings can present in an unclear way leading to more than one possible interpretation. In the case presented the central question to be answered was whether the soot cave resulting from a contact shot and the permanent cavity resulting from a distance shot with semi-jacketed bullets fired off by a long gun can morphologically be distinguished.
Methods. Ballistic shooting experiments were performed. Semi-jacketed bullets and a hunting gun similar to that used in the present case were used for several contact and distance shots into ballistic soap and gelatin. The resulting wound channels were compared.
Results. Although the above-mentioned findings pointed towards a contact shot, shooting experiments showed it must have been a distance shot. These findings fitted with the results of the examination of gunshot residues by electron microscope.
Conclusions. The morphology of the wound channel resulting from a long gun firing off half-jacketed bullets allows to differentiate between distance shots and contact shots.