Visual and Chemical Variability in Gunpowder Residue Deposition on Different Fabric Media

• NCJ Number: 216390
• Journal: Canadian Society of Forensic Science Journal Volume: 39 Issue: 3 Dated: September 2006 Pages: 115-124
• Author(s): J. Marshall
• Date Published: September 2006
• Length: 10 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: Canada

Annotation

This study examined the deposition of gunpowder particles on different fabrics (cotton, nylon, fleece, denim, satin, wool, and corduroy) at variable distances from which the gun was fired (range); it also compared the distribution of gunshot residues and lead on pigskin in order to determine whether one cloth type would be a suitable substitute for skin tissue when analyzing range.

Abstract

Cotton was determined to be the best substitute for pigskin in simulating gunpowder deposits. Analysis of the visible gunpowder particle dispersion found significant variation among the types of fabrics. Denser materials such as wool and corduroy had a low quantity of particles adhering to their surfaces, such that a diameter could not be measured around the bullet hole. Shinier fabrics such as satin and nylon tended to disperse the powder particles more than the other materials. Within the 10 shots fired for each fabric, cotton had the widest deviation, and denim had the smallest deviation. The remainder of the fabrics were somewhere in between, which would likely be due to variation from shot to shot for each of the test materials at a range of 12.7 cm. The visual quantity of powder particles also varied significantly among fabric types. Fabrics such as cotton and satin had relatively denser particle patterns; whereas wool, corduroy, and nylon showed light quantities of particles deposited. The distribution of soot around the bullet holes was consistent among the fabrics. The only exception was cotton, for which the soot spread out at a greater distance at a range of 12.7 cm.. The chemical examination used sodium rhodizonate to observe the patterns of lead dispersion among the cloth types. Ranges were 5.1 cm (2 inches) and 25.5 cm (10 inches). The procedure was repeated using samples of fresh pigskin at a range of 12.7 cm. 4 figures and 6 references