Firearm and Toolmark Identification
Firearm and Toolmark Identification
Firearm and Toolmark Identification (FTI), often mistaken for “ballistics,” and sometimes referred to as “forensic ballistics,” or “ballistics fingerprinting,” is the analysis of firearms, ammunition, and toolmark evidence used to establish whether a particular firearm was used in the commission of a crime. FTI consists of the analysis and comparison of microscopic features present on the metal surfaces of ammunition, firearms, and other objects (e.g. screwdrivers, knives, pipes, etc.). Since the 1930’s, virtually all jurisdictions (including Oregon) freely admit such evidence; however, several recent federal decisions indicate increasing judicial discomfort with the “science” of FTI.
Background and How It Works
- Ballistics Fingerprinting (Wikipedia) — Basic summary.
- Ballistics, Lisa Steele’s ABA Summary — More detailed summary of the legal issues.
- FirearmsID.com: An Introduction to Forensic Firearm Identification <http://www.firearmsid.com/A_Introduction.htm> — Thorough introduction to the scientific discipline, including definitions of terms, basic principles, and illustrations of the methods of testing and the features examined.
- Firearm and Toolmark Identification — Powerpoint presentation that include images.
- Strengthening Forensic Science in the United States: A Path Forward, National Academy of Sciences 150 – 55 (2009) — Discussion of what sorts of conclusions FTI seeks to make, how examiners make their analyses, and an assessment of the scientific basis for FTI (providing criticism).
The “science” of firearm and toolmark identification, is the process of individualization, which compares one solid object with another solid object to identify whether the objects were either (1) part of the same object (e.g. fragments of an exploded bullet), (2) had come in contact with one another (e.g. the firing pin and the casing), or (3) shared similar class or individual characteristics (e.g. bullets shot from the same gun that might share particular patterns). Individualization, through either “Pattern-Fit” or “Pattern Transfer” comparison, examines whether there is a match between the two objects. While pattern-fit describes a situation akin to matching puzzle pieces (where the more complex the pattern, the more likely the match is unique or significant), pattern transfer describes the pattern of impressions or striations created by a collision between the working surface of a tool and the surface of the material being inspected. Microscopic imperfections in the metal of firearms are purported to leave unique (or at least distinctive) striations in the softer metal of the ammunition as a result of rifling or other mechanical interactions. Therefore, in order to determine that the pattern on the evidence, e.g. a casing, came from a particular firearm, it would be crucial to know whether the working surface of the firearm is in fact unique.
Other related examinations of firearms to which experts are called to testify:
- serial number restoration
- suspected gunshot residues
- function testing of firearms
- determination of muzzle to target distance
- kind (make/model) of firearm responsible for firing recovered bullets or cartridge cases
- crime scene reconstruction
- intercomparison of both unknown evidence and test fired bullets, cartridge cases, and shotshell components with one another
Certifying Bodies and Standards
- The Scientific Working Group for Firearms and Toolmarks (SWGGUN) – While there is no certifying body, per se, SWGGUN has developed a series of consensus guidelines for the firearm and toolmark discipline and disseminates SWGGUN guidelines, studies, and other findings that may be of benefit to the forensic community.
- In response to the NAS’ criticism of deficits in the scientific process used in toolmark identification (above), SWGGUN developed the following protocols for examiners: SWGGUN Systemic Requirements/Recommendations for the Forensic Firearm and Toolmark Laboratory.
- The Association of Firearm and Toolmark Examiners (AFTE) – Professional organization that offers guidance on methods of toolmark examination, but does not provide specific protocols. AFTE publishes the Association of Firearm and Toolmark Examiners Journal, which is the primary professional, peer reviewed journal for the firearm and toolmark community.
Sample and Data Collection
- National Integrated Ballistic Information Network (NIBIN) – The result of integration of the FBI’s DRUGFIRE database with the ATF’s CEASEFIRE database, NIBIN allows Federal, State and Local officials to access Integrated Ballistic Identification Systems (IBIS) to acquire digital images of the markings made on spent ammunition recovered from a crime scene or a crime gun test fire and then compare those images against earlier NIBIN entries via electronic image comparison.
- INTERPOL Ballistic Information Network (IBIN)
- Other INTERPOL Firearms tracking programs
- National Clearinghouse for Science, Technology & the Law Forensic Database – A huge database of not only journal articles, but law reviews, books, websites, internet articles, legislation, cases, etc.
- NCST Bibliography: Toolmark Examiner Training
- NCST Bibliography: 3-D Assessment of Toolmarks
- Forensic Science International
- Journal of Forensic Science
- Sébastien Charles, et. al., Examination of Firearms Review: 2007 to 2010, 16th International Forensic Science Symposium, INTERPOL 5 – 14 (2010).
Relevant Oregon Statutes
Or. Rev. Stat. § 40.410 – OEC Rule 702 governs admissibility of expert testimony. Bases of experts’ knowledge may be knowledge of machining process, knowledge with the microscopic appearance of working surfaces, or knowledge of the results of research performed on consecutively manufactured tools.
Under sufficiently reliable conditions, an expert in firearm and toolmark identification may testify to characteristics of firearm evidence in a criminal trial in Oregon. State v. Henderson, 182 Or. 147 (1947). However, Oregon appellate courts have not had occasion to reconsider admissibility of firearm and toolmark identification under the Brown/O’Key analysis. State v. Brown, 297 Or. 404, 417 (1984) (finding polygraph evidence inadmissible because of disagreement in the field); State v. O’Key, 321 Or. 285, 299–300 (1995) (identifying the seven Brown factors regarding scientific evidence admissibility as 1) the technique’s general acceptance in the field; 2) the expert’s qualifications and stature, 3) the use the expert made of the technique; 4) the potential rate of error; 5) the existence of specialized literature; 6) the novelty of the invention; and 7) the extent to which the technique relies on the subjective interpretation of the expert). O’Key indicated the Oregon Supreme Court’s endorsement of the Daubert standard, which requires courts to analyze not only expert credibility but also the credibility of the scientific procedures themselves, and also held the Brown factors relevant to analyses of non-novel scientific evidence – such as FTI.
As a preliminary matter, it is also crucial to note that the proponent of expert evidence under ORS § 40.410 (FRE Rule 702) carries the burden of proving the reliability of the expert testimony and underlying scientific methods. Under Brown/O’Key, the validity and pertinence of scientific evidence must be evaluated in light of: 1) whether the theory or technique can be and has been tested; 2) whether the theory or technique has been subject to peer review and publication; 3) known or potential rate of error; and 4) degree of acceptance in relevant scientific communities. State v. O’Key, 321 Or. at 299 (1995).
Members of the scientific community have expressed concerns about FTI; particularly regarding lack of empirical data, peer review, and rates of error. See, generally Adina Shwartz, A Systematic Challenge to the Reliability and Admissibility of Firearms and Toolmark Identification, 6 Colum. Sci & Tech. L. Rev. 2 (2005). In addition, while some empirical data does exist (and is growing as a result of NIBIN), experts in forensics law have expressed the opinion that FTI “is subjective in nature, founded on scientific principles and based on the examiner’s training and experience.” Theory of Identification, Range of Striae Comparison Reports, and Modified Glossary definitions—An AFTE Criteria of Identification Committee Report, 24 Ass’n Firearm & Toolmark Examiners J. 336 (1992). Finally, more generally, many in the forensic science community rebut the notion that individualization and uniqueness should even constitute the conceptual foundations for forensic identification (i.e. that it is even possible to determine that a particular bullet came from a particular gun as opposed to another). Simon A. Cole, Forensics Without Uniqueness, Conclusions Without Individualization: The New Epistemology of Forensic Identification, 8 Law, Probability and Risk 233 (2009).
The significant challenges to forensic science made in the last few years (what one commenter likened to a “siege”) have not gone unanswered. K.M. Pyrek, Forensic Science Under Siege: The Challenges of Forensic Laboratories and the Medico-Legal Investigation System, Academic Press, Amsterdam (2007). Tests have been issued to determine rates of error, see, e.g. L. Scott Chumbley, Quantification of Toolmarks, Doc. No. 230162, and experts have also responded to the more general claims against individualization. See Ronald Nichols, The Scientific Foundations of Firearms and Tool Mark Identification – A Response to Recent Challenges, reprinted in FirearmsID.com (Sept. 2006).
While Oregon’s appellate courts have not dealt with the admissibility of FTI, there have been cases in other jurisdictions that discuss the issue, and some that have excluded or limited expert testimony and evidence regarding FTI:
- United States v. Glynn, 578 F. Supp. 2d 567 (S.D.N.Y. 2008) (holding that Government’s ballistics expert would be limited to opining only that a firearms match was “more likely than not”).
- United States v. Monteiro, 407 F. Supp. 2d 351 (D. Mass. 2006) (holding that 1) expert testifying as to match between cartridge case and firearm must be qualified and must follow established standards with respect to documentation and peer review; 2) fact that purported expert test-fired firearm only after partially reconstructing it with replacement parts did not render his testimony as to that firearm inadmissible; 3) underlying scientific principle that firearms leave unique marks on ammunition is reliable, for purposes of determining admissibility of expert testimony; 4) state police sergeant was qualified as expert; and 5) sergeant’s testimony was inadmissible because it failed to comport with standards for documentation and peer review).
- United States v. Green, 405 F. Supp. 2d 104 (D. Mass. 2005) (Government ballistics expert’s toolmark testimony was admissible, despite concerns about subjective testing methods and lack of evidence as to error rates in field, so long as it was limited to expert’s observations; expert would not be allowed to testify as to his conclusion that match he had found excluded all other guns as source of shell casings in question).
- United States v. Kain, Criminal No. 03-573-1 (E.D. Pa. 2004) (resulting in a plea bargain prior to trial court ruling, defense raised a challenge to the statistical likelihood of a random firearm with the same class characteristics as the recovered evidence having sufficiently similar individual characteristics to create a misidentification) – See the Amicus Brief, republished in the Journal of Philosophy, Science and Law, which discusses attacking identifications on the basis of inadequate statistical support.
- Sexton v. State, 93 S.W.3d 96, 101 (Tex. Crim. App. 2002) (Theory that unfired shell casings could be identified by toolmarks was not shown to be reliable in aggravated assault trial, despite expert qualifications, where expert did not have magazine or magazines that allegedly made marks available for testing, and expert did not testify that he was familiar with magazine manufacturing process).
Search Warrant Required
While no case is perfectly on point, Ryan’s article argues that lawful seizure of a firearm alone, without a valid search warrant, does not provide sufficient grounds for a ballistics test because such a test would reveal characteristics that are not plainly visible. See State v. Cardell, 180 Or. App. 104,109-110 (2002); State v Portrey, 134 Or. App. 460,465 (1995).