American Gun: Aurora Shooter James Holmes Tries to Use NAS Report to Preclude Expert Firearm Testimony

James Holmes, who allegedly fatally shot twelve people and injured dozens more at the midnight premiere of "The Dark Knight Rises," at an Aurora movie theater, has moved to preclude expert opinion testimony that would link the bullets used in the shootings to his firearms. If granted, the motion of course would cause significant problems for the prosecution in proving the charges against Holmes. So, what is the basis of Holmes's motion, and is it likely to be successful?

According to the motion,

In 2009, the National Research Council of the National Academy of Sciences published a report to Congress identifying the needs of the forensic science community, which has brought to light the serious problems with various types of forensic evidence on a national scale....The NAS Report noted several problems with firearm identification. The NAS Report concluded that "the scientific knowledge base for toolmark and firearms analysis is fairly limited."...In order to make the process of individualization more precise and repeatable, the report concluded "additional studies should beperformed."...The report further concluded that the protocol developed by the Association of Firearms and Toolmark Examiners ("AFTE") detailing when an examiner may reach a certain conclusion — which is the industry standard by which examiners conduct their examinations —was not defined in a sufficiently precise way for examiners to follow, particularly in relation to when an examiner can "match" two samples. The report berated the protocol, stating "[t]his AFTE document, which is the best guidance available for the field of tool mark identification, does not even consider, let alone address, questions regarding variability, reliability, repeatability, or the number of correlations needed to achieve a given degree of confidence."

Specifically, the report noted that

[The] determination of a match is always done through direct physical comparison of the evidence by a firearms examiner, not the computer analysis of images....[E]ven with more training and experience using newer techniques, the decision of the toolmark examiner remains a subjective decision based on unarticulated standards and no statistical foundation for estimation of error rates.

According to Holmes, the results of the NAS report render firearm identification evidence inadmissible under Colorado Rule of Evidence 702, which provides that

If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.

Holmes's contention is that, in effect, the NAS report renders firearm identification evidence too unreliable to assist the trier of fact (the jury).

So, is he likely to be successful? Likely not. State v. Langlois, 2 N.E.3d 936 (Ct.App.Ohio 6th 2013), is fairly typical of the response of courts when presented with a Rule 702 challenge based on the 2009 NAS report. According to the court in Langlois,

Even a sympathetic reading of the 2009 report...indicates its primary purpose was to serve as a catalyst for reassessing the scientific premises underlying the various fields of forensic science and to summarize the current state of the research in those fields relative to the challenges raised in the report. It was not its purpose to opine on the long-established admissibility of tool mark and firearms testimony in criminal prosecutions, and indeed the NRC authors made no recommendations in that regard. Having identified certain limitations existing in this discipline, as they exist in other forensic sciences, they called for more research on "the variability in marks made by an individual tool," including "the rigorous quantification and analysis of sources of variability."

That urging, however, hardly makes what firearms examiners do junk science, or "voodoo" as counsel termed it. Even those courts which have placed limits on a firearms examiner's opinion testimony, due to concerns with the physical or scientific theory on which it is based, have not gone that far.

In other words, the court in Holmes's case might place limits on expert firearm testimony, but it is exceedingly unlikely to exclude it.

-CM