Volume 38, Issue 3 (May 1993)
Collection Efficiency of Gunshot Residue (GSR) Particles from Hair and Hands Using Double-Side Adhesive Tape
Experiments were carried out to sample GSR particles (GSRs) from hair using double-side adhesive coated aluminum stubs (the tape-lift method). Although it was claimed in the literature that double-side adhesive tape is not suitable for sampling GSRs from hair, we have not encountered problems with this method. In laboratory experiments it was possible to find GSRs even 24 h after shooting if the hair had not been washed. No significant difference in collection efficiency was found between this technique and the more complicated method of swabbing the hair using a comb with a solvent-damped cloth (the swabbing-and-comb method). It was found that 200 to 300 dabbings are necessary to achieve maximum collection efficiency from hair with the double-side adhesive. As assessed subjectively, it was noted that stickiness is lost after about 100 dabbings. This method has been used in casework in Israel for about a year and a half and, in some cases, GSRs were found in samples from hair but not in samples from hands. We have also studied collection efficiency from hands of the double-side adhesive. It was found that 50 to 100 dabbings are necessary to achieve maximum collection efficiency, while stickiness appeared lost after about 20 to 30 dabbings. No substantial danger of skin debris concealing GSRs was observed.