Comparative Bullet Lead Analysis Evidence: Valid Inference or Ipse Dixit?
30 Pages Posted: 9 Dec 2012
Date Written: September 27, 2003
Compositional comparisons of bullet lead, where questioned samples obtained from a crime scene are compared with known-source bullets seized from a suspect, a forensic practice known as comparative bullet lead analysis (CBLA), has been admitted into evidence by courts for over 30 years as evidence of criminal guilt if the compositions were considered "analytically indistinguishable."
The first part of this paper reviews the state of the technological and scientific record, with special emphasis on the permissibility of the expert witness' ultimate inference as to whether the crime scene bullet originated from the same manufacturer, molten source, batch, or box, as the bullets attributable to the suspect.
The second part analyzes the state of the scientific record in light of the governing legal standards, namely, the Frye general acceptance test and the competing validation standard enunciated in Daubert and its progeny the Supreme Court's 1999 decision in Kumho Tire Co., Ltd. v. Carmichael.
In the final analysis, we conclude that courts and practitioners were seduced for over three decades by the sophistication of the analytical instrumentation and precision of the generated data, and proffered evidence that was meaningless and had no probative value for judicial proceedings.
Keywords: forensic, compositional bullet lead analysis, CBLA, comparative bullet lead analysis, evidence, reliability
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