Gunshot Residue Detection and Interpretation: Final Report for the National Institute of Justice

• NCJ Number: 164663
• Author(s): P. R. De Forest
• Date Published: January 1996
• Length: 12 pages
• Agencies: NIJ-Sponsored

Annotation

Procedural aspects of detecting and interpreting gunshot residue (GSR) are described, including high-speed photographic study, GSR detection at crime scenes, muzzle-to-target distance estimation, photoluminescence techniques, GSR detection on shooter hands, trace metal detection, GSR pattern interpretation, propellant particle categorization, and GSR detection by low-dose x-rays.

Abstract

Features of GSR formation have been studied using high-speed photographic techniques, and knowledge of the rate of movement of the GSR cloud toward the shooter has shed light on certain interpretative problems associated with the analysis of GSR on hands. The use of a tunable high-intensity light source to detect GSR at crime scenes has been a valuable technique. Transfer techniques have been used to estimate muzzle-to-target distance but not without problems related to partially burned propellant particles and effect on lead cloud and bullet wipe. The use of photoluminescence methods to estimate muzzle-to-target distance is demonstrated. In addition, experiments have been conducted to detect GSR on the hands of shooters, including native fluorescence experiments and experiments with various chemical reagents designed to induce fluorescence. Trace metal detection techniques are employed by many jurisdictions due to problems associated with detecting GSR on the hands of shooters. Detailed studies of the stability and retention of nitrites arising from propellant particles have been conducted, and methods have been developed to categorize propellant particles and to separate, identify, and quantify nitro derivatives of diphenylamine found in GSR. In addition, a low-dose x-ray instrument commonly used in mammography is being studied for possible application to GSR analysis. 5 references