Three people convicted of murder have been released from prison because their cases were tainted by a now discredited theory that bullets found at a crime scene could be linked to bullets found in possession of suspects. Nearly five years after the FBI abandoned its so-called comparative bullet lead analysis, the FBI has yet to complete its review of nearly 2,500 cases where law enforcement used such evidence to investigate a case.
So far, the agency has found 187 cases where so-called comparative bullet lead analysis evidence was not only used in the investigation, but came into play at trial where FBI experts provided testimony. It has notified prosecutors in those cases where testimony from its experts ``exceeds the limits of the science and cannot be supported by the FBI,' one agency letter says.
At least three convictions that of a Colorado man who served 12 years in prison for a double slaying, a Florida man who served 10 years after being convicted of killing his wife, and an Oregon man convicted of a triple slaying have recently been overturned. All three men are now free.
Comparative bullet lead analysis was based on the theory that lead bullets pick up trace elements such as copper, antimony, arsenic, bismuth and silver during manufacturing. When the soft metal is shaped into bullets and packaged, bullets in the same box would contain similar amounts of the trace elements, the theory went. FBI lab technicians compared bullet fragments from a crime scene with bullets possessed by suspects. If the trace elements closely matched, prosecutors backed by FBI testimony would argue the suspects' guilt.
Defence attorneys say the analysis appeared to be a miracle of science: It required a small nuclear reactor, once housed at an FBI lab at the Hoover Building in Washington, D.C., and relied on the expertise of only a handful of qualified FBI agents. FBI experts wowed jurors by explaining how gamma rays, energy released from bombarding a bullet with neutrons, could be measured to make a match.
``Sure, you have this whiz-bang, whipper-dipper machine that looks at all the elements of the universe, but it doesn't mean anything,' said attorney Dave Wymore, a former director of the Colorado public defenders office who fought successfully to exclude such evidence in a triple-murder case and won an acquittal in 1999.
The FBI began the tests in the mid-1960s. It quit in 2005, after the National Research Council of the National Academy of Science concluded that while its methods of measuring trace elements were sound, its conclusions were flawed. Millions of other bullets could contain trace elements in identical quantities, the council said. That rendered the FBI's box-by-box conclusions meaningless. FBI lab spokeswoman Ann Todd said the agency has reviewed about 2,000 cases and is waiting on information from prosecutors who may have used the bullet evidence at trial in the remaining 500 cases. In cases where an FBI expert testified, the agency is reviewing trial transcripts.
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