The scientific methods behind forensic investigations have come under increasing scrutiny, as defendants challenge convictions based on evidence that, once considered infallible, was later determined to be erroneous. The scrutiny includes firearms analysis, often called ballistics, after a report last month by the President’s Council of Advisors on Science and Technology questioned whether the science of analyzing firearms is sound enough to support the standard of proof that is constitutionally required for a criminal conviction, the Boston Globe reports. The report has sent ripples throughout legal and law enforcement communities, as shown by a motion by lawyers in one of Massachusetts’ most high-profile cases, the murder trial of former New England Patriots player Aaron Hernandez. Lawyers asked a judge this month to toss expert testimony related to a firearm police have linked to the case.
“There are new issues here with the idea of ballistic certainty … there’s not much science to it,” said Linda Kenney Baden, a Hernandez lawyer. Still, the report’s findings have been widely criticized. Forensic scientists note that the council lacked representation from ballistics experts. Defense lawyers for Hernandez said the issue is ripe for an immediate appellate court review. At issue is the process of toolmark analysis, in which examiners attempt to match the physical characteristics of a gun to markings on a spent bullet or casing. Investigators have long contended that a microscopic view can determine whether a specific firearm caused the markings on a specific bullet or casing. Researchers have questioned the science behind the analysis, saying it is more of a subjective review by an examiner than a scientific process. Last month’s government report questioned whether courts have gone far enough in setting restrictions for questionable evidence in forensic investigations, saying jurors tend to believe any statements given by an expert witness.