By firing a gun, the bullet passes through the barrel followed by flame, gases, metallic particles, soot and to some extent (partially) burned gunpowder. These gunshot residues (GSRs) play an important role in forensic investigations of gun-related violence, as they may help to analyse who has been involved in the shooting [
1‐
5], to differentiate entrance and exit wounds, to determine muzzle-to-target distance and muzzle-to-target angle [
6]. The chemical composition of GSRs has even been recognized as a kind of “signature” for the fired ammunition and its manufacturer [
4]. Furthermore, GSRs are also detectable on the hands after mere handling and/or loading of a gun without shooting and can even be transmitted from one person to another, for example from police officers to suspects [
1,
7,
8].
For any crime scene investigation, it is crucial to preserve the scene as much as possible and not to disturb any physical evidence — especially in case of trace evidence, like GSRs, where minimal impact can destroy essential evidence. Scene photographs should document the original position of the body and any evidence. GSRs should subsequently be secured by forensic experts and undergoing further chemical tests [
9]. The different ballistic aspects are worked up by different scientific disciplines, whereas internal and external ballistics are covered by specialists from the police or scientific fields like physics or mathematics. In contrast to that, end/wound ballistics is predominantly the task area of legal medicine. Main part thereby is the examination of the body, whereas the number of gunshot wounds, the shooting distance and the bullet entry angle are determined. For the determination of the shooting distance and discrimination of entry and exit wound, GSRs play an important role [
10]. In the vast majority of close-range shots, GSRs are found predominantly around the entrance wound or, in cases of a contact shot, they are also located subcutaneously at the entrance wound margins. In some cases, depending on muzzle-to-skin distance and type of gun, gunpowder is even “tattooing” the skin, which is unique for bullet entry regions and not found at exit wounds [
11‐
13]. GSRs have been extensively described to help to discriminate entrance and exit wounds [
13‐
15]. The presence of GSRs has even been postulated to be an exclusion criterion for exit wounds [
16,
17]. Nowadays, there is increasing evidence that GSRs could also be expected at exit wounds. Di Maio reports that especially cylindrical gunpowder particles can travel along the whole bullet path and can therefore be found at the exit area [
14]. Große Perdekamp et al. showed in their experimental setting with gelatine blocks and pigskin that the highest amount of GSRs is found around the bullet entry and decreases along the shot channel, whereas it increases again at the bullet exit region. They proved the existence of GSRs along the whole bullet path. In contact shots, this phenomenon was explained with the formation of a temporary cavity that leads to an additional energy release with consequently pumping gunpowder particles to both directions (bullet entry and exit) after its collapse. Thus, burned and unburned flake-shaped particles are spotted around the exit region [
18].
For this report, we present a case, where a similar uncommon pattern of unburned GSRs has been found in the hair around the exit wound after a fatal headshot of an 84-year-old male.