The science of matching a particular bullet to a particular gun is sufficiently shaky that Maryland courts will now impose stricter limits on such ballistics testimony, the state's Supreme Court ruled. The 4-3 decision ruled that a firearms expert who testified at a murder trial shouldn’t have been allowed to offer an unqualified opinion that bullets recovered from a crime scene came from the suspect’s gun, the Associated Press reports. Maneka Sinha, a law professor at the University of Maryland Carey School of Law, said it was groundbreaking for a state’s highest court to take a critical look at the scientific foundations of such evidence and find that the type of testimony that courts have been relying on for years is unreliable. Sinha was on a team of public defenders in the District of Columbia that litigated a trial-level case in which a judge restricted firearms testimony in a similar way. “While challenges to this type of evidence have been made increasingly, very few high courts have taken up the issue,” Sinha said. The ruling ordered a new trial for Kobina Ebo Abruquah, who was convicted of murder in 2013 after the court allowed a firearms examiner to testify without qualification that bullets at a crime scene were fired from a gun that Abruquah had admitted was his.
Chief Judge Matthew Fader, who wrote the ruling, noted that the majority doesn’t question that firearms identification is generally reliable. He wrote that it can be helpful to a jury in identifying whether patterns and markings on “unknown” bullets or cartridges “are consistent or inconsistent with those on bullets or cartridges known to have been fired from a particular firearm.” Fader also noted that it’s possible that experts who are asked the right questions or have the benefit of additional studies and data may be able to offer opinions “that drill down further on the level of consistency exhibited by samples or the likelihood that two bullets or cartridges fired from different firearms might exhibit such consistency.” “However, based on the record here, and particularly the lack of evidence that study results are reflective of actual casework, firearms identification has not been shown to reach reliable results linking a particular unknown bullet to a particular known firearm,” Fader wrote. The ruling pointed out that firearms identification has existed as a field for more than a century, and for most of that time it has been accepted by law enforcement and courts without significant challenge. But recent reports have questioned the foundations underlying firearms identification, leading to greater skepticism. For example, the court noted that reports issued since 2008 by two groups of experts outside of the firearms and toolmark identification fields that have been critical of the Association of Firearm and Tool Mark Examiners Theory, which is the leading methodology used by firearms examiners.