NCJ Number
159180
Journal
Journal of Forensic Sciences Volume: 40 Issue: 6 Dated: (November 1995) Pages: 1082-1085
Date Published
1995
Length
4 pages
Annotation
This article reports on Israel's casework experience in the detection of gunshot residue (GSR) particles on samples from hands, hair, and clothing over the period 1989 through 1994.
Abstract
Israel's kit for sampling GSR's from suspects consists of two 25-mm diameter aluminum stubs coated with double-side adhesive tape (Scotch Tape no. 465, 3M company). From 1979 until the end of 1990, the procedure was as follows: one stub was used to sample the right hand, and the other was used for the left hand. The instructions were to dab the stub against the hand until the adhesive tape had lost its stickiness. Until 1987 SEM/EDX analyses for GSR's were conducted by a manual search of approximately a quarter of the stub area, using a CamScan 3 scanning electron microscope (SEM) combined with a Tracor- Northern TN 5500 energy dispersive X-ray (EDX) system. Since the beginning of 1987 the analyses for GSR have been conducted with an automated search system attached to a CamScan 4 SEM equipped with a motorized stage drive and a four-samples holder, combined with a Tracor-Northern TN 5500 EDX system. Samples were carbon coated and the basic search area was 10 x 8mm 2. The overall "success" rate on the examined samples was approximately 10 percent. Although this rate is low, it has an inherent benefit for the probative value of this type of evidence, since it diminishes the danger of finding GSR's due to accidental contamination. In a high percentage (39 percent) of the positive GSR samples, only one particle was found. This result is consistent with a low detection rate of GSR's in the casework samples. 4 tables and 13 references