Feature Article,September 2006

This month's article comes from Ron Nichols and is reprinted here with his permission.


The Scientific Foundations of Firearms and Tool Mark Identification –
A Response to Recent Challenges
Ronald Nichols


Recently, an article was published in The Columbia Science and Technology Law Review entitled “A Systemic Challenge to the Reliability and Admissibility of Firearms and Toolmark Identification.”[2] The author, Dr. Adina Schwartz, is an Associate Professor with the John Jay College of Criminal Justice and the Graduate Center, City University of New York. Dr. Schwartz uses the framework of an amicus brief written on behalf of the defense in the case United States v. Kain[3] to expound on her arguments as to why “all firearms and toolmark identifications should be excluded until the development of firm statistical empirical foundations for identification and a rigorous regime of blind proficiency testing.”[4]

Outlining her treatise, Schwartz first discusses the scientific issues related to firearms and tool mark identification. These scientific issues include:

  • The types of tool marks
    • Class
    • Subclass
    • Individual
  • Three major sources of misidentification
    • Individual characteristics are comprised of non-unique marks
    • Subclass characteristics may be confused with individual characteristics
    • Individual marks of a particular tool change over time
  • A call for statistical treatment using DNA as an analogy
  • The lack of adequate proficiency testing
  • Fundamental problems not cured by development of “computerized firearms database”

Subsequent to her discussion of the scientific issues, Schwartz discusses some of the case law related to firearms and tool mark identification. She does this to illustrate, in her opinion, that, “no state or federal court – either before or after Daubert – has understood the scientific problems with firearms and toolmark identification.”[5]

The purpose of this article is to review and assess the arguments made by Schwartz and to evaluate the basis of support cited to support those arguments. It will be demonstrated throughout this article that the challenge offered by Schwartz is not as substantiated as an uncritical review of her article would suggest. There are numerous instances in which studies and articles are inappropriately quoted or inaccurately paraphrased. During the discussion of some of the scientific issues, there is an apparent lack of understanding of the relative significance as applied to the science of firearm and tool mark identification. While the author was apparently aware of the large number of articles available that can be used to address many of these issues, there was no mention of them made in her argument.[6] Furthermore, there were instances in which research into some of these primary resources, rather than reliance on some secondary resources, would have been much more enlightening.

   Download full review by clicking the links below.

Review of AS Admissibility (Adobe pdf) 235 KB

PowerPoint Presentation Summary (PP mht file) 1.5 MB

[1] D-ABC, Distinguished Member AFTE, AAFS Fellow

[2] Schwartz, Dr. Adina. “A Systemic Challenge to the Reliability and Admissibility of Firearms and Toolmark Identification.” The Columbia Science and Technology Law Review, Volume VI, 1-42.

[3] United States v. Kain, Crim. No. 03-573-1 (E.D. Pa. 2004). Subsequently published as “A Challenge to the Admissibility of Firearm and Toolmark Identifications: Amicus Brief prepared on Behalf of the Defendant in United States v. Kain, Crim. No. 03-573-1 (E.D. Pa. 2004).” The Journal of Philosophy, Science, &Law, Vol. 4, December 7, 2004.

[4] Supra note 2, at 42.

[5] Supra note 2, at 3.

[6] Personal communication with Bruce Moran, Criminalist with the Sacramento County District Attorney’s Forensic Science Laboratory via e-mail on April 16, 2005. Moran provided Dr. Schwartz with personal notes citing in excess of 100 different citations dealing with firearm and tool mark identification.

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