Issue Date: March 2, 2009
Board's Report Leads To Overturn Of Murder Conviction
After serving 10 years in prison for the 1991 murder of his wife, Jimmy Ates was released from the Okaloosa County Jail, in Crestview, Fla., on Dec. 17, 2008. Ates is the first person in the country to have a conviction overturned as a consequence of a 2004 report by the National Academies' Board on Chemical Sciences & Technology (BCST), which dismissed a long-standing protocol for bullet-lead analysis used by the Federal Bureau of Investigation.
Results of the forensic test in question were admitted as evidence in Ates's trial, which ultimately resulted in a guilty conviction. The scientific validity of the forensic technique, known as compositional bullet-lead analysis (CBLA), had been questioned on numerous occasions over the years by defense teams and the press when the results were presented as evidence in criminal trials across the country. So the FBI asked the National Research Council to conduct a review of the scientific merit of CBLA, according to Ann Todd, a special agent with the FBI's Public Affairs Office.
Forensic scientists have long used CBLA as a tool to link bullet fragments found at a crime scene to bullets found in the possession of a suspect. CBLA uses chemical analysis to determine how closely the elemental composition of one bullet matches that of another and statistical analysis to assess the significance of the relationship.
The result of the BCST study was a report called "Forensic Analysis: Weighing Bullet Lead Evidence." The chemical analyses examined received a passing grade. The findings indicate that the analytical technique at the center of CLBA, inductively coupled plasma-optical emission spectroscopy, is accurate and reliable in identifying and measuring trace elements present in bullet-lead samples. Furthermore, the report concludes that the seven elements (arsenic, antimony, tin, copper, bismuth, silver, and cadmium) selected for analysis are appropriate choices for differentiating samples. And the report confirms that this elemental analysis procedure is the best one currently available.
But the report throws into question the statistical tests that FBI forensic scientists have been using to make sense of the results of elemental analyses from different bullet samples. In addition, the report suggests that the significance of the established relationship between bullet-lead samples based on the results of the chemical and statistical analyses could be easily and inadvertently misrepresented by prosecutors or misinterpreted by a trial jury. Because this can threaten the fairness of a trial, the report recommends that CBLA testimony be used with caution.
The study helped the FBI decide in 2004 to stop using CBLA. This decision was significant: From the early 1980s through 2004, the FBI conducted bullet-lead analyses for about 2,500 cases submitted by federal, state, local, and foreign law enforcements agencies. In most of these, the results of the analyses were not part of the prosecution's cases, but in almost 500 cases, the results were used as evidence in a trial, according to a 2005 FBI press release, which Todd confirms.
The FBI is reviewing those cases, specifically focusing on trials where testimony involving CBLA results may have been inaccurately portrayed, according to the bureau. Ates now is out of jail as a result of the BCST report and the scrutiny it triggered.
- Chemical & Engineering News
- ISSN 0009-2347
- Copyright © American Chemical Society