Friday, November 21, 2003

National Academy of Sciences to Criticize FBI Bullet-Matching Techniques

Bullets are made in batches. Different batches may have different chemical characteristics and lead content. And bullets from the same batch may be similar in composition. For many years, FBI forensic experts have relied on these seemingly reasonable premises when they want to match a bullet from the crime scene with a box of bullets found in the suspect's basement. Indeed, matching bullets by lead content can fairly be called a well-established forensic technique.

But since retiring from his career as a highly respected FBI metallurgist, William Tobin has been questioning the soundness of lead-matching evidence. Research published by Tobin and others has suggested that bullets from the same batch can vary significantly in their content, and that bullets from different lead sources can appear chemically similar. Partly in response to Tobin's critiques, the FBI commissioned the National Academy of Sciences to look into the matter.

The Associated Press is now reporting that a draft NAS report will include recommendations that the FBI take steps to correct dubious methods and procedures in its lead-matching techniques. Here's the story as posted by MSNBC. Update: TalkLeft has an informative post too.
Fed. R. Evid. 702: If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.