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Identification and Comparison of Electrical Tapes Using Instrumental and Statistical Techniques: I. Microscopic Surface Texture and Elemental Composition

NCJ Number
218482
Journal
Journal of Forensic Sciences Volume: 52 Issue: 3 Dated: May 2007 Pages: 610-629
Author(s)
John V. Goodpaster Ph.D.; Amanda B. Sturdevant M.S.; Kristen L. Andrews B.S.; Leanora Brun-Conti B.S.
Date Published
May 2007
Length
20 pages
Annotation
This study analyzed 67 rolls of black electrical tape that represented 34 brands, using scanning electron microscopy (SEM) and energy dispersive spectroscopy in an effort to distinguish the tapes by microscopic surface texture and elemental composition.
Abstract
The study found differences among the tapes in surface roughness, calendering marks, and filler particle size, including between some rolls of the same tape brand. The study also found that the surface texture of any given roll of electrical tape was reproduced over both short and long distances in the tape roll. In terms of elemental composition, the relative amounts of magnesium, aluminum, silicon, sulfur, lead, chlorine, antimony, calcium, titanium, and zinc varied significantly between brands. In some cases, the relative amounts of these elements could be linked to the year of manufacture. Thirty-six classes of tape were identified within the sample population. In a single-blind study, questioned tape samples were correctly matched with known exemplars. Two case studies demonstrate how tape recovered from an improvised explosive device was linked to tape recovered from a suspect. The tape samples used in this study were drawn from the electrical tape reference collection of the Bureau of Alcohol, Tobacco, and Firearms. Only black tapes with a nominal width of 0.75 in. were included in the study. The samples were visibly indistinguishable upon superficial examination and were of the most common color and width. This article describes the instrumental analysis and the data analysis. 11 tables, 16 figures, and 23 references