Comparative bullet-lead analysis

Comparative bullet-lead analysis

Comparative bullet-lead analysis (CBLA) also known as Compositional bullet-lead analysis) is a now discredited and abandoned[1] forensic technique which used chemistry to link crime scene bullets to ones possessed by suspects on the theory that each batch of lead had a unique elemental makeup.[2]

The technique was first used after U.S. President John F. Kennedy's assassination in 1963.[2] From the early 1980s through 2004 the US Federal Bureau of Investigation conducted about 2,500 analyses on cases submitted by law-enforcement groups. The results of these analyses had often been questioned by defense lawyers and the press, so the FBI finally asked the United States National Academy of Science's Board on Science, Technology, and Economic Policy to research the scientific merit of the process.

In 2004 the Board's study was summarized in "Forensic Analysis: Weighing Bullet Lead Evidence." The Board determined that the chemical analyses were being performed correctly and were probably sufficient to determine correlation between two bullets from separate sources (the analysis used plasma-optical emission spectroscopy to identify trace elements in the bullets). The report also concluded that the seven trace elements selected for the analyses (arsenic, antimony, tin, copper, bismuth, silver and cadmium) are acceptable for sample correlation. The report finally concluded that the procedure is the best available method for such correlations. The greatest caveat in the report was that the statistical tests as applied by the FBI could cause confusion and misinterpretation when transmitted to prosecutors or when explained to a trial jury. Because of the significance of this weakness, the report concluded that the analysis should be used with caution. This report helped the FBI decide in 2004 to voluntarily cease offering the analysis to law-enforcement entities. The National Academy of Sciences never required that the FBI stop using the test.[2]

CNN PRESENTS Encore Presentation: Reasonable Doubt examined the unreliability of this technique.[3] It has been discontinued as of September 1, 2005.[4]

The U.S. government has fought releasing the list of the estimated 2,500 cases over three decades in which it performed the analysis, which may have led to false convictions. According to the FBI, only 20% of the 2,500 tests performed introduced the CBLA results into evidence at trial.

In 17 December 2008, Jimmy Ates was released from a Florida prison after serving ten years on the conviction of having murdered his wife, a conviction obtained largely on the strength of a bullet-lead analysis. His conviction was overturned as a consequence of the 2004 report.[5] On March 10, 2011, Jimmy Ates was retried and convicted again of having murdered his wife. Despite initial reports that his first conviction had been obtained largely on the strength of bullet-lead analysis, this turned out to be untrue. The bullet-lead analysis was completely meaningless in his first as well as his second trial. The evidence of Jimmy Ates' guilt turned out to be overwhelming. He admitted in three (3) separate interviews to being inside his home when his wife made a 911 call. This was a call he was both unaware of and refused to believe had actually occurred. Additionally, seven (7) separate witnesses placed both of the Ates' vehicles at the home subsequent to the 911 call. A time-delayed device was then used to set a time-delayed fire by the front picture window of the Ates' residence which faced the busy main Highway 189 in Baker, Florida. The murder and the victim's body were at the other end of the home. The fire was reminiscent of those often seen in arson for profit cases where the arsonist needs an alibi. There was much more evidence presented of Jimmy Ates' guilt. Mr. Ates' case was attempted to be used by advocates as an example in hopes of over-turning other convictions. However, to date, there have been no other reported convictions that have been over-turned as a result of using bullet-lead analysis. Apparently, the original prosecutor who had agreed to over-turn the first conviction of Jimmy Ates without a hearing, and without consultation with law enforcement, the original prosecutors or the victim's family, announced his resignation during the second trial.

References

  1. ^ http://news.yahoo.com/s/ap/20100118/ap_on_re_us/us_discredited_bullet_evidence
  2. ^ a b c Solomon, John (2007-11-18). "FBI's Forensic Test Full of Holes: Lee Wayne Hunt is one of hundreds of defendants whose convictions are in question now that FBI forensic evidence has been discredited". Washington Post. http://www.washingtonpost.com/wp-dyn/content/article/2007/11/17/AR2007111701681.html. 
  3. ^ "CNN.com". CNN. http://transcripts.cnn.com/TRANSCRIPTS/0605/07/cp.01.html. 
  4. ^ http://www.fbi.gov/pressrel/pressrel05/bullet_lead_analysis.htm
  5. ^ Chemical & Engineering News, 2 March 2009, "Board's Report Leads to Overturn of Murder Conviction", p. 32


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