Statistical Challenges in the Quantification of Gunshot Residue Evidence

• NCJ Number: 246179
• Journal: Journal of Forensic Sciences Volume: 58 Issue: 5 Dated: September 2013 Pages: 1149-1155
• Author(s): Romain Gauriot M.Sc.; Lawrence Gunaratnam M.Sc.; Rossana Moroni Ph.D.; Tapani Reinikainen Ph.D.; Jukka Corander Ph.D.
• Date Published: September 2013
• Length: 7 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

This article discusses gunshot residue, the formation of extremely small particles resulting from the discharge of a firearm.

Abstract

The discharging of a gun results in the formation of extremely small particles known as gunshot residue (GSR). These may be deposited on the skin and clothing of the shooter, on other persons present, and on nearby items or surfaces. Several factors and their complex interactions affect the number of detectable GSR particles, which can deeply influence the conclusions drawn from likelihood ratios or posterior probabilities for prosecution hypotheses of interest. We present Bayesian network models for casework examples and demonstrate that probabilistic quantification of GSR evidence can be very sensitive to the assumptions concerning the model structure, prior probabilities, and the likelihood components. This finding has considerable implications for the use of statistical quantification of GSR evidence in the legal process. Abstract published by arrangement with Wiley.