FBI asked to downplay forensic bullet analysis

Found on New Scientist on Tuesday, 10 February 2004
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The technique, called "compositional analysis of bullet lead" (CABL), profiles the contents of seven metals which contaminate bullets when they are produced from melted battery lead. CABL implies guilt by revealing, for example, that bullets found in boxes belonging to a suspect are "analytically indistinguishable" from bullets found at the crime scene.

Since developing the technique in the 1960s, the FBI has presented incriminating CABL evidence in numerous murder cases. This has to be tempered in the future, says the report, published on Tuesday by the US National Research Council.

The panel found that bullets from different sources get mixed together in individual boxes as ammunition is distributed. The FBI itself found bullets from 14 different sources in one individual box, say the researchers.

Also, millions of identical bullets can come from a single smelting operation, and so an individual box of them cannot be incontrovertibly linked to a specific crime scene.

The question is what's more important for judiciary: to make people feel safer by putting someone behind bars who could be guilty, or admitting that they don't catch as many murderers as they want to.