A scientific panel has issued its report onthe FBI's methodology of bullet analysis :

A scientific panel is questioning a method used by the FBI to match bullets from crime scenes, a finding that could give defense lawyers a new route to attack prosecution evidence. In seeking to tie bullets from a crime scene to others found in a suspect's possession, the FBI analyzes the lead for traces of seven other metals, a system that the report from the National Research Council said was sound.

However, the study questioned a statistical analysis method known as chaining in which trace elements in a series of bullets in a box are compared. It noted that the bullets sold together in one package are not necessarily all from the same batch of melted lead.

News of major problems with the non-scientific identification technique began surfacing in November.

It seems that contrary to what FBI agents have testified to in court the past few decades, bullets that appear chemically identical can come from different batches of lead. FBI experts have testified repeatedly in court that each time lead is melted and cast, its composition changes just enough to create a unique chemical signature for each batch.....Recent scientific studies have concluded that this premise is wrong. Studying blocks of lead used in the manufacture of bullets, researchers have found the same chemical makeup in batches made at different times. They also have reported that the concentration of trace elements can vary significantly in the same casting of lead.

If the skeptics are right, the matches found by FBI lab technicians are meaningless.

Update: The Innocence Project and the National Association of Criminal Defense Lawyers (NACDL), through President-Elect (and IP co-founder) Barry Scheck, have issued this press release, call for the reopening of cases in light of the National Academies report on FBI bullet lead analysis.

The National Academies report, Forensic Analysis: Weighing Bullet Lead Evidence is available here.A joint preliminary position paper by the Innocence Project and NACDL on improving the forensic sciences is here.