Judging Firearms Evidence

76 Pages Posted: 19 Jan 2023 Last revised: 14 Apr 2023

See all articles by Brandon L. Garrett

Brandon L. Garrett

Duke University School of Law

Eric Tucker

Duke University School of Law

Nicholas Scurich

University of California, Irvine - School of Social Ecology

Date Written: February 3, 2023

Abstract

Firearms violence results in hundreds of thousands of criminal investigations each year. To try to identify a culprit, firearms examiners seek to link fired shell casings or bullets from crime scene evidence to a particular firearm. The underlying assumption is that firearms impart unique marks on bullets and cartridge cases, and that trained examiners can identify these marks to determine which were fired by the same gun. For over a hundred years, firearms examiners have testified that they can conclusively identify the source of a bullet or cartridge case. In recent years, however, research scientists have called into question the validity and reliability of such testimony. Judges have also viewed such testimony with increased skepticism, especially after the Supreme Court set out standards for screening expert evidence in Daubert v. Merrell Dow Pharmaceuticals, Inc.

In this Article, we detail over a century of caselaw and examine how judges have engaged with the changing practice and scientific understanding of firearms comparison evidence. We first describe how judges initially viewed firearms comparison evidence skeptically and thought jurors capable of making firearms comparisons themselves—without an expert. Next, judges embraced the testimony as comparison experts offered more specific and aggressive claims, and the work spread nationally. Finally, we explore the modern era of firearms caselaw and research, with an explosion of reported judicial decisions. Judges increasingly express skepticism and adopt a range of approaches to limit in-court testimony by firearms examiners. We conclude by examining lessons regarding the gradual judicial shift towards a more scientific approach towards expert testimony. The more-than-a-century-long arc of judicial review of firearms evidence in the United States suggests that over time, scientific research can displace tradition and precedent to improve the quality of justice.

Keywords: Firearms, tool marks, Daubert, Frye, scientific evidence, reliability, error rates

Suggested Citation

Garrett, Brandon L. and Tucker, Eric and Scurich, Nicholas, Judging Firearms Evidence (February 3, 2023). Duke Law School Public Law & Legal Theory Series No. 2023-10, Available at SSRN: https://ssrn.com/abstract=4325329 or http://dx.doi.org/10.2139/ssrn.4325329

Brandon L. Garrett (Contact Author)

Duke University School of Law ( email )

210 Science Drive
Box 90362
Durham, NC 27708
United States
919-613-7090 (Phone)

HOME PAGE: http://www.brandonlgarrett.com/

Eric Tucker

Duke University School of Law ( email )

210 Science Drive
Box 90362
Durham, NC 27708
United States

Nicholas Scurich

University of California, Irvine - School of Social Ecology ( email )

4312 Social and Behavioral Sciences Gateway
Irvine, CA 92697
United States

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