A study of gunshot residue distribution for close-range shots with a silenced gun using optical and scanning electron microscopy, X-ray microanalysis and infrared spectroscopy.

Detailed physical and chemical analysis of gunshot residue deposited in the nearest vicinity of a submachine gun alone and with a sound suppressor was performed. The studies were inspired by recent shooting cases with the use of a firearm with a silencer and the need to estimate the shooting distance to human body naked and covered with clothing. A series of experiments were performed in the shooting range using a machine pistol and the appropriate ammunition cal. 7.65mm Browning. Targets were placed in the range of 0-30cm from the gun and covered either with white cotton fabric or a porcine skin that mocked people's clothing and the naked skin. Both the organic and inorganic residue were examined by means of optical microscopy, infrared spectrometry as well as scanning electron microscopy and energy dispersive X-ray spectrometry. The influence of factors, such as sound suppressor, shooting distance and the substrate type on the mechanism of particles spread and their availability for research was established and discussed.