Surgical mask as an alternative sampling site for gunshot residue analysis

Abstract

Gunshot residue (GSR) has been identified in the oro-nasal cavities and in various areas of the face. However, there is no study in the literature about the outcome of the analysis if the mouth and nose are covered with a mask. The purpose of this study is to experimentally ascertain whether GSR detection can be made on surgical masks. Twelve civilians wearing facemasks were divided into six groups of two, each consisting of a shooter and an accompanying person. A single shot was fired by the mask wearing shooters of all six groups in an outdoor and indoor shooting range. The inner surface, outer surface, and strap of the mask were the three areas where we investigated for the presence of GSR. GSR particle counts of the shooter were higher than those of accompanying person. Analysis after outdoor range shootings yielded fewer particles than indoor range shootings. The most particles were detected on the outer surface of the masks, and the least on the inner surface. All analyzes performed on the shooters' mask revealed significantly higher number of particles compared to accompanying persons. The results showed a significant difference in the quantity of GSR particles identified, which could aid in distinguishing between the shooter and the accompanying person. The outer surface of the mask has been determined to be the most useful sampling location in this regard, as it is the sample where the difference is most prominent.