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Firearms, Tool Marks, and Ballistics

National Academy of Sciences Report - See pp. 150-155 for the National Research Counsel's assessment of the discipline of Toolmark and Firearms Identification.

The 2016 PCAST Report found that "firearms analysis currently falls short of the criteria for foundational validity, because there is only a single appropriately designed study to measure validity and estimate reliability. The scientific criteria for foundational validity require more than one such study, to demonstrate reproducibility. Whether firearms analysis should be deemed admissible based on current evidence is a decision that belongs to the courts. If firearms analysis is allowed in court, the scientific criteria for validity as applied should be understood to require clearly reporting the error rates seen in appropriately designed black-box studies (estimated at 1 in 66, with a 95 percent confidence limit of 1 in 46, in the one such study to date)." See p. 112.

Ballistic Imaging - The National Academies Press, 2008. Provides information about the range of acceptable conclusions in this field, as well as the lack of error rate and subjectivity of the comparison techniques.

May 6, 2013 DOJ Letter - this letter from the DOJ regarding the results of a US DOJ and FBI review of lab reports and testimony of FBI lab examiners in the Willie Manning case finds that testimony stating that a specific gun fired a specific bullet "to the exclusion of all other guns in the world" is not scientifically supported.

Firearms and Toolmarks Subcommittee this Scientific Area Committee (part of the OSAC) has taken over the work previously done by the Scientific Working Group For Firearms and Toolmarks (SWGGUN). The SAC will focus on standards and guidelines related to the examination of firearm and toolmark evidence. This includes the comparison of microscopic toolmarks on bullets, cartridge cases, and other ammunition components and may also include firearm function testing, serial number restoration, muzzle-to-object distance determination, tools, and toolmarks.

Association of Firearm and Tool Mark Examiners - is an international organization dedicated to the advancement of Firearm and Toolmark Identification. See the Admissibility Resource Kit for links to opinions, transcripts, motions, briefs and articles supporting and opposing the practice of firearm identifications.

Training Materials

The University of Utah Health Sciences Library has several firearms tutorials posted which cover information about the different types of firearms and how they work, ballistics (the science of the travel or a projectile in flight), patterns of tissue injury, laboratory methods, and examination of gunshot residue. The tutorials provide basic foundational information as well as more technical information about firearm function.

NIJ Firearm Examiner Training - The National Institute of Justice has an online training that includes topics such as Bullet Comparison and Identification, Gunshot Residue and Distance Determination, and Toolmark Identification. The training provides both a general understanding of firearms/firearms evidence and gives a detailed explanation of techniques used by firearm examiners.

Firearms and Toolmarks Overview - this document created by the Georgia Bureau of Investigation provides a clear description of the analyses performed by firearms and toolmark examiners. It is presented from the perspective of a crime lab, so it does not question the reliability of any of the techniques presented, but it is a helpful document for attorneys because it explains the procedures used and illustrates them with photographs.

Articles

• Recent news articles - this page contains links to recent press coverage of local and national cases involving firearm and ballistics evidence and is updated regularly.
• This July 7, 2016 NIST post on a 3D Ballistics Database discusses new techniques used in firearm-toolmark comparisons.
• Ballistics Evidence Under Fire - this article by Paul Gianelli was published in the Winter 2011 edition of the American Bar Association's journal, Criminal Justice. It addresses how courts in Daubert jurisdictions have handled challenges to firearm/projectile comparison evidence.
• Hypothesis Testing of the Critical Underlying Premise of Discernible Uniqueness in Firearms-Toolmarks Forensic Practice - this article by William A. Tobin and Peter J. Blau argues that existing studies that are typically presented in court as support for firearm/projectile comparisons are fatally flawed and thus are of no value for validation of the techniques used. The authors offer a solution that would allow a scientifically defensible opinion to be proffered to courts until comprehensive and meaningful hypothesis testing can be conducted by the mainstream scientific community. Click on the button that says "Download This Paper" to download the entire article for free.
• Analysis of experiments in forensic firearms/toolmarks practice offered as support for low rates of practice error and claims of inferential certainty - this article by Clifford Spiegelman and William A. Tobin evaluates experiments used to justify conclusions of "individualization" or specific source attribution to "100% certainty" and "near-zero" rates of error claimed by firearm toolmark examiners in court testimonies and suggests approaches for establishing statistical foundations for this firearm and toolmark comparisons.
• Automatic comparison and evaluation of impressions left by a firearm on fired cartridge cases - 2014 article by F. Riva and C. Champod in the Journal of Forensic Sciences. Addresses new solutions to decrease the subjective component of firearm/spent cartridge case comparisons.
• A Systematic Challenge to the Reliability and Admissibility of Firearms and Toolmark Identification by Adina Schwartz, in The Columbia Science and Technology Law Review
• Summary of the FBI Laboratory’s Gunshot Residue Symposium, May 31-June 3, 2005 - this article summarizes the findings of a group of scientists and practitioners who met to address issues with gunshot residue analysis and attempt to create guidelines for this type of analysis. This document references several studies that have been published regarding contamination of subjects and proper collection, testing, and reporting procedures.
• Forensic Science International published a research article by Michael Cook entitled, "Gunshot residue contamination of the hands of police offices following start-of-shift handling of their firearm" in Nov. 2016. The study found that 85 percent of officers had 3-component GSR particles on their hands immediately following the start-of-shift handling of their firearms.
• FBI Lab Scraps Gunfire Residue by Julie Bykowicz, The Baltimore Sun. 2006 article which discusses a 2001 contamination study and the FBI's decision to no longer analyze gunshot residue in its investigations.
• The Controversy Concerning Gunshot Residues Examinations by Dennis L. McGuire, M.S., Forensic Magazine - discusses the lack of a uniform standard for GSR analyses based upon validated studies. States that until those studies are completed, "positive determinations of GSR should be seriously scrutinized."
• Knife and Saw Toolmark Analysis in Bone: A Manual Designed for the Examination of Criminal Mutilation and Dismemberment by Steven A. Symes, Ph.D. et al. for the U.S. Department of Justice. Available through the National Criminal Justice Reference Service (2010)

Opinions, Briefs, Motions, and Affidavits

• Williams v. United States - Jan. 21, 2016 decision from the DC Court of Appeals in which Judge Catherine Easterly's concurrence states that a firearms and toolmark examiner should be preculded from testifying with unqualified, absolute certainty.
• Motion for Appropriate Relief - Grounds for the MAR drafted by Hoang Lam of NCPLS include new evidence on the unreliability of comparative bullet lead analysis and new evidence on the assumptions and limitations underlying firearm and toolmark identification.
• Affidavit of Stephen Bunch (2008) - This 10-page affidavit gives Bunch's position how an examiner should describe the certainty of an identification, including use of the terms "practical certainty," "absolute certainty," and "to a reasonable degree of scientific certainty." The affidavit also gives his position on validity testing and subclass characteristics. Bunch re-evaluated the firearm identification work of SBI analysts in some cases in 2010 and 2011 at the request of the state.
• Commonwealth v. Pytou Heang SJC-10376 (2011) - Massachusetts Supreme Court gives guidelines to "ensure that expert forensic ballistics testimony appropriately assists the jury in finding the facts but does not mislead by reaching beyond its scientific grasp." The Court requires the firearms examiner to provide pretrial to the defense documentation in the form of measurements, notes, sketches or photographs that support the examiner's ultimate opinion. The Court urges the use of photographs showing the comparison. The Court says in a footnote, "the role of the expert is to assist the jury in determining fact, not simply to say 'take my word for it.'" If the expert is allowed to offer opinion testimony, the expert should avoid the phrases "practical impossibility" and "absolute certainty." "Reasonable degree of scientific certainty" should be avoided because if suggests that forensic ballistics is a science. "Reasonable degree of ballistic certainty" can be used. Link to briefs (See Appellant's arguments on ballistics not being a science)
• U.S. v Love, Case No. 2:09-CR-20317-JPM (Feb. 8, 2011). The Western District Court of Tennessee ruled that a firearm examiner could not testify that he is "absolutely certain" or "practically certain" as to his results. The opinion states that "Bunch testified that absolute or practical certainty is impossible in toolmark identification."
• U.S. v Anderson, Case # 2009 CF1 20672 (Sept. 3, 2010) The Superior Court of the District of Columbia ruled that the firearms examiner may declare a firearms "match" to a "practical certainty" or to a "reasonable degree of certainty within the field of firearms and toolmark identification." The examiner may not express his opinions to a "reasonable degree of scientific certainty" or state that there is a match to an exact statistical certainty. The examiner may not state that it would be "practically impossibile" or "virtually impossible" for another firearm to have contributed the same marks.
• U.S. v St. Gerard,United States Army Trial Judiciary, Fifth Judicial Circuit, Germany (June 7, 2010). The Court concluded that toolmark examination did not meet the Daubert standard in terms of proficiency testing, peer review and publication, error rate calculations, and the NAS Report's questions about the reliability of toolmark examination. The Court found that testimony indicating that a shell casing must have come from the AK-47 would be unreliable and exluded testimony that it would be a practical impossibility for the cartridge case to have been fired from any weapon other than the seized AK-47.
• U.S. v. Willock, (Mar. 23, 2010). United States District Court, D. Maryland, Northern Division. Defendant Mouzone moved to exclude firearm examiner's testimony arguing his conclusion is unreliable and scientifically invalid. Court adopted recommendations of Chief Magistrate Judge Grimm who recommended that Mouzone's Rule 702 motion be denied consistent with other federal decisions addressing admissibility of firearm toolmark evidence, but restricted the degree of certainty with which experts may express their opinions due to two National Research Counsel reports. Grimm recommended complete restriction on the characterization of certainty because some of the examiner's conclusions were based on a non-testifying examiner whose qualifications, proficiency, and methods were unknown.