Fate and Behavior of Gunshot Residue—A Review

Abstract

A review of the literature concerning the fate and behavior of gunshot residue (GSR) is presented. A number of concomitant parameters including firearm and ammunition type, plume and GSR material characteristics, travel distances, chemical composition and GSR morphology are critically discussed in relation to their effects on the distribution and deposition, transfer and persistence processes of GSR. The underlying mechanisms associated with such processes are also considered. Knowledge of these processes on GSR materials could provide valuable information concerning scene preservation and subsequent forensic sampling. The number of GSR particles deposited can vary significantly with each firearm discharge, highlighting the potential to produce distinctive data in each individual case. With the continual development and compositional changes of new ammunition types, further evaluation of the effect these processes may have on GSR evidence and their possible influence on the interpretation of the analytical results should be given due consideration.

Fate and Behavior of Gunshot Residue: Recreational Shooter Vehicle Distribution

“…The total number of characteristic GSR particles seen in each vehicle varied from 51 to 876 (Table ). The persistence of GSR depends largely upon a number of variables, such as the time since discharge and the number of shots fired . Rosenberg and Dockery suggest that the detection window for GSR on hands may be days rather than hours.…”

“…An association between the varying levels of characteristic GSR particles seen within recreational shooters’ vehicles and GSR transfer processes is to be expected. Such processes include the frequency of use of the vehicle, the frequency of firearms‐related activities of the user of the vehicle, and the types of guns/ammunition used .…”

“…These include being used to transport a shooter to and/or from the scene of a shooting and the discharge of a firearm from within or near to a vehicle . The level of GSR transfer in such instances is thought to be closely linked to the nature and duration of contact between the contaminated individual or surface and the vehicle (see for a more detailed account of how these contaminant processes affect GSR distribution). Before sampling a vehicle, it is important to determine a strategy based on the case circumstances, taking into consideration the most likely places of GSR transfer in the vehicle.…”

“…This is due to the potential for direct transfer of GSR to occur between the recently contaminated shooter and/or firearm and these surfaces. The exterior of a vehicle is thought to have a lower retention rate than the interior, due to both the exposure to the external environment and its typical impermeable surface texture not facilitating particle persistence .…”

The analysis of organic and inorganic gunshot residue from a single sample

“…When a firearm is discharged, GSR escapes through weapon openings and may subsequently deposit on surfaces in the near vicinity of the fired weapon [5,6]. As a result, GSR could become evidence consequent to the criminal use of a firearm [7] and its detection and identification could provide valuable information in forensic investigations of the incident.…”