NCJ Number
192034
Journal
Journal of Forensic Sciences Volume: 46 Issue: 6 Dated: November 2001 Pages: 1342-1351
Date Published
November 2001
Length
10 pages
Annotation
This study characterized bullets by lead isotope ratio analysis and trace element analysis in two homicides.
Abstract
In the first case, lead isotope analysis yielded "no match" between the fatal bullet and the bullets from the suspect's box. Further, arsenic was detected in the fatal bullet but not in the suspect's bullets. Bullets in the suspect's box were homogeneous with respect to trace element compositions and isotope ratios. Establishing or disproving the common origin of a particular bullet with a box of ammunition represents a situation suited to isotope ratio and elemental comparison analyses. The "no match" conclusion in this case was consistent with polygraph results obtained from one of the suspects. In the second case, with two bullets collected at the crime scene and with 163 bullets of many different types seized at various locations, lead isotope analysis did not show matches among the bullets examined; however, there was an interesting correlation. The bullets in evidence bag #243 had compositions similar to one another, and the bullets from bag #97 had compositions similar to one another despite having different manufacturers' headstamps on the cartridges. The bullet populations from the two bags were distinctly different in trace elements, with all of the bullets from bag #243 having much lower concentrations of trace constituents than the bullets in bag #97. The investigators conjectured that the results could be explained if the bullets had been reloaded, with the bullets in each having a common source. The firearms examiner immediately recognized that the evidence ammunition had indeed been reloaded. Although this information was of technical interest, it did not contribute to the investigation. 6 tables, 3 figures, and 9 references