Reports and Publications
To assist the Texas Forensic Science Commission in a pending review of traditional toolmark-comparison testimony, the Yale Law School Forensic Science Standards Practicum submitted this report on the range of approaches that courts, legal commentators, and scientists have proposed for presenting toolmark-comparison evidence in trial settings. The report addresses four major topics: (1) the case law on source attributions for firearms and other tools; (2) consensus standards from the forensic-science community; (3) expressing uncertainty when presenting source attributions; and (4) alternative modes of interpreting the microscopic similarities and differences in compared items.
- Statement of the TX Forensic Science Commission Regarding “Alternate Firearms Opinion Terminology”, Texas Forensic Science Commission
Dec. 2021 statement Addressing a USDOJ document that instructs firearms examiners to avoid using terminology such as the weapon “could have fired” the bullets or cartridge cases, “consistent with” or “could not be excluded” as having fired the bullets or cartridge cases.
Effective Aug. 15, 2020
In the firearm/toolmark pattern match Uniform Language for Testimony and Reports (ULTR), the new guidance for Department of Justice firearm examiners includes:
[A]n examiner shall not:
- assert that a ‘source identification’ or a ‘source exclusion’ conclusion is based on the ‘uniqueness’ of an item of evidence.
- use the terms ‘individualize’ or ‘individualization’ when describing a source conclusion.
- assert that two toolmarks originated from the same source to the exclusion of all other sources.
These new requirements are in addition to prior ULTR guidance that an examiner shall not claim infallibility, zero error rate, or absolute certainty.
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.
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.
See pp. 150-155 for the National Research Counsel’s assessment of the discipline of Toolmark and Firearms Identification.
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.
From the Blog
- The National Institute of Justice has published several reports on novel techniques that are being investigated in order to improve forensic analysis. Take a look at the reports below to learn about some of the latest techniques that are being developed and to get a forecast of what techniques you may see coming soon to …
- SBI to Begin Using New Reference Standard to Assist Examiners in Identifying Cartridge Casings, 9/10/2012A new reference standard for comparing cartridge casings has been developed by the National Institute of Standards and Technology (NIST). The standard is known as SRM 2461, Standard Casing. It was developed to assist firearms examiners by ensuring that the equipment used to match cartridge cases to those in the National Integrated Ballistic Information Network …
- Two Bullets, One Gun?, 1/20/2012By Alyson Grine, Defender Educator, UNC School of Government In State v. Britt, __ N.C. App. __, __ S.E.2d __ (Dec. 6, 2011) the North Carolina Court of Appeals addressed the admissibility of expert testimony regarding firearms and toolmark identification. The facts, in brief: Nancy Britt, a Wake County school teacher, was shot and killed …
Research study on bullet and cartridge case comparison finding the odds of disagreement between examiners about the evidential strength of a comparison were approximately five times larger in the blind than in the non-blind procedure, with disagreement about 42.3% and 12.5% of the proposed conclusions, respectively. Also, the odds that their proposed conclusion was reported as the final conclusion were approximately 2.5 higher for the higher-status examiners than for lower-status examiners.
- NIBIN Toolkit for Prosecutors, Ultra Electronics Forensic Technology
Explains how the NIBIN database works to search for possible connections between bullets or casings fired a separate crime scenes. Explains that every NIBIN lead must be verified by a firearms examiner. The NIBIN technician report of a lead is not sufficient reliable and should not be the basis of testimony. Advises prosecutors not to provide information about NIBIN use in discovery. Provides sample direct examination questions.
- Document outlining NIST's approach to conducted scientific foundation reviews (including data sources used, evaluation criteria, and expected outputs) of DNA mixture interpretation, bitemark analysis, digital evidence, and firearms examination.
Jan. 28, 2020 article in Science & Justice finding that bias occurs in non-blind peer reviewed bullet and cartridge case comparisons. Higher status examiners have a large influence on the outcome of a discussion. Blind peer review may reduce the probability of bias during peer review.
- Garrett, B.L, Scurich, N, & Crozier, W.E. (2020)
Article by Adina Schwartz, in The Columbia Science and Technology Law Review
- Gunshot residue contamination of the hands of police offices following start-of-shift handling of their firearm
Forensic Science International published a research article by Michael Cook 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.
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.
- Hypothesis Testing of the Critical Underlying Premise of Discernible Uniqueness in Firearms-Toolmarks Forensic Practice
Article by William A. Tobin and Peter J. Blau that 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. Article is available for free download.
- Analysis of experiments in forensic firearms/toolmarks practice offered as support for low rates of practice error and claims of inferential certainty
Article by Clifford Spiegelman and William A. Tobin that 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.
- 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)
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.”
Article by Paul Gianelli
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.
Article that 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.
- In person and live webcast, Sponsored by Indigent Defense Services, the Duke Law Center for Criminal Justice and Professional Responsibility, and the Wilson Center for Science and Justice
- 4-day no-cost virtual program offered by FTCoE and NIJ
- Free Webinar offered by NACDL. Presenter: Brendan Max
- Presenter: Keith Morris. Offered by CSAFE, on June 14, 2021. Recording and materials are available.
- Presenter: Maria Cuellar. Offered by CSAFE, on June 14, 2021. Recording and materials are available.
- Presenter: Heike Hofmann. Offered by CSAFE, on June 14, 2021. Recording and materials are available.
- Speakers: Brandon Garrett, Nicholas Scurich, and William Crozier. Presented by CSAFE. Recording available.
This presentation, now available to view for free, was given as a part of the Center for Statistics and Applications in Forensic Evidence’s (CSAFE) 2020 All Hands Meeting. The meeting brings together researchers, forensic partners, and interested community members to discover potential areas for collaboration, highlight the organization’s achievements, and discuss goals for the future.
This presentation, given by Dr. Heike Hofmann, a professor of statistics at Iowa State University, discusses the results of a previous study related to comparison standards in Firearms and Toolmark analysis. The presentation also addresses the objectives of research being done in that area going forward.
- To view the presentation in it’s entirety click here
- To view only the slides click here
The importance of taking on prosecution forensic experts on behalf of clients cannot be overstated. It is no mystery how powerful forensic evidence is to jurors. Yet countless wrongful convictions are, in fact, the result of inaccurate, faulty, or unchallenged forensics. This practical workshop will prepare defense counsel to challenge unreliable expert testimony using a mock case involving firearm and digital evidence.
Tuition is $795.00. Program dates are January 16-18, 2020 at the University of Arizona James E. Rogers College of Law at Address: 1201 E. Speedway, Tucson, AZ 85721. Accommodations (not included in tuition) are offered at the Aloft Tucson University, just 1 mile from the law school. Special hotel block rate is $179.00 (plus tax)/night. Hotel block expires 12/24.
The National Criminal Defense College will offer a program in Tucson, Arizona on challenging faulty forensic testimony.
Tuition is $795.00. Program dates are January 16-18, 2020 at the University of Arizona James E. Rogers College of Law at Address: 1201 E. Speedway, Tucson, AZ 85721. Accommodations (not included in tuition) are offered at the Aloft Tucson University, just 1 mile from the law school with a special hotel block rate of $179.00 (plus tax)/night. (Hotel block expires 12/24.)
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. The program is for criminal justice professionals and you must create a login to access the content.
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.
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.
An international organization dedicated to the advancement of Firearm and Toolmark Identification. See the Admissibility Resource Kitfor links to opinions, transcripts, motions, briefs and articles supporting and opposing the practice of firearm identifications.
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
Sample direct and cross-examinations of various forensic witnesses, including a firearm/toolmark expert, fingerprint expert, pathologist, DNA expert, and other forensic experts.
The National Forensic Science Technology Center created this website to explain in simplified terms the principles of each type of forensic analysis and how the analysis is performed. Topics include DNA, digital evidence, fingerprints, firearms, trace evidence, blood stains, and more.
Information about a new research database and techniques used in firearm-toolmark comparisons.
COA found no plain error in allowing firearm identification testimony. Former NCSCL analyst Wilson testified in detail about her methodology, but provided little information about application of the method to the case at hand.
COA held that trial court did not abuse its discretion in admitting the testimony
of the State’s GSR expert because he followed the State Crime Lab’s procedures as
required to meet Rule 702(a)’s reliability requirement where defendant made statement upon GSR collection that he had been asleep during the 5+ hour period between shooting and collection.
After applying Daubert, the court concluded that the expert testimony in the case should be limited because the conclusions were not supported by a quantifiable or replicable scientific process.
Decision on a Frye Motion requesting that the court preclude all ballistic expert testimony comparing shell casings from the crime scene to a gun found in one of the defendants’ car. The court concluded that an expert cannot offer opinions that are not supported by the relevant scientific community. Testimony by an expert that is unfounded or that uses subjective terms are not permitted as they could mislead the jury.
After applying the Daubert factors, the court reached the conclusion that ballistic matching lacks the scientific integrity to make statements of certainty. The court limited the ballistics expert testimony to only stating that the gun could not be excluded as a potential source of the bullet.
The court allows the ballistics expert testimony, but limits the testimony to say that the gun in question could not be eliminated as a source of the bullet.
The court affirmed the admissibility of the Government’s expert witness’s statement of certainty concerning the ballistic evidence. The expert testified that the markings were, “unique to that gun, and that gun only.” Id. at 346. Due to a failure to object by the defense and a lack of binding law that says otherwise, the inclusion of this statement was affirmed.
The court finds that ballistics science is admissible, and notes the level of subjectivity and the impossibility of a perfect match in this field of science. The court prohibits the expert testimony from saying that the ballistic match is to a scientific, practical, or absolute certainty to exclude all other firearms.
The court finds that ballistics examination lacks the rigor and certainty of other forensic sciences, and there a limit is needed on the degree of confidence given during testimony. The court limits testimony to “more likely than not”.
Defendant filed a motion to exclude expert testimony which was denied in part and granted in part. The court held that the expert could provide testimony concerning toolmark evidence, but could not testify that a match was found to a degree of certainty which excludes all other firearms in the world from being the source.
Although the defendant’s motion to exclude testimony was denied, the court held that the toolmark expert may not testify that a match was found to an “absolute” or “practical” certainty. This conclusion was reached after evidence was presented that suggested this level of certainty was impossible.
The Court holds that it will allow ballistics testimony with limitations. The expert testimony can include things such as the methodology and the fact that a match was found, but the expert cannot make claims of certainty that the match excludes all other possible firearms in the world. Id. at 124.
The court ruled that toolmark evidence is relevant, helpful, and reliable if offered by a qualified examiner who followed the AFTE theory. Id. at 569-570. There should be documentation (photographs, notes, etc.) of the conclusions reached to allow confirmation by a second qualified examiner on how an identification was reached. Id. This documentation should also be sufficient for a defense expert to challenge if one is sought. Id. The testimony of the examiner is admissible so long as the examiner is prevented from making unsupported claims about the degree of certainty of their identification. Id. Additionally, the court holds that, “the government should be required to strictly and timely comply with its Fed.R.Crim.P. 16 obligations . . .” concerning this testimony. Id.
A SCL analyst performed an experiment measuring the direction and distance that shell casings traveled when a gun was fired at various angles and testified to the results, offering opinions about location of the shooter. On appeal, counsel argued that the tests were not “substantially similar.” The COA held that Rule 702 governs admission of expert evidence, including experimental evidence.
Decision on Frye Motion making a finding that the relevant scientific community consists of the fields of forensic science, scientific methodology in studies and statistics, and psychology. The court ruled that the examiner may testify about class characteristics, but may not offer qualitative opinions on matters not adequately supported by the relevant scientific community, including the significance of marks other than class characteristics as the reliability of that subjective practice has not been established.
Motions and Briefs
- Order Allowing Testing and Inspection of Firearms Evidence and to Transport Evidence to Defense Expert
Order granted in 2009, filed under seal until case was resolved.
Trial court denied the motion, but initially prohibited the State from offering testimony “that the bullets in question were fired from the same weapon” because of potential for misleading the jury. However, the testimony was allowed after the trial court found the defense opened the door to the testimony during opening statements.
- Motion to Exclude Firearm Identification Testimony, Memorandum of Law, State’s Brief in Response to Defendant’s Motion, and Order
2011 motion in limine by Richard Ramsey. Example of how to use the National Academy of Sciences report and other professional standards in a motion to exclude or suppress forensic evidence. Transcript of motion’s hearing available upon request.
Motion filed by David Botchin and Mark Rabil.
Firearms in the News
- ShotSpotter held in contempt of court, by Matt Chapman and Jim Daley, Chicago Reader, 7/26/2022
- Lawsuit: Chicago police misused ShotSpotter in murder case, by Garance Burke and Michael Tarm, AP, 7/22/2022
- Savannah spends $489K on ShotSpotter but doesn’t keep data on effectiveness, by Jake Shore, The Current, 6/30/2022
- ‘We have to try something’: Durham police chief says ShotSpotter could address violent crime, by Crystal Price, CBS17, 5/27/2022
- The Field of Firearms Forensics Is Flawed, by David L. Faigman, Nicholas Scurich, and Thomas D. Albright, Scientific American, 5/25/2022
- How AI-powered tech landed man in jail with scant evidence, by Garance Burke, Martha Mendoza, Juliet Linderman, and Michael Tarm, AP, 3/5/2022
- Why a High-Ranking FBI Attorney Is Pushing ‘Unbelievable’ Junk Science on Guns, by Radley Balko, Daily Beast, 2/9/2022
- DC public defenders seek wider review into fingerprints, firearms evidence, by Jack Moore, WTOP, 1/26/2022
- William Bailey, Rougemont, NC
- Peter D. Barnett, Hayward, CA
- Jack Benton, Lubbock, TX
- Curtis Caldwell, NC
- Steven Carpenter, Cary, NC
- Kathleen Clardy, Raleigh, NC
- William E. Conrad, Fredericksburg, VA
- Frankie E. “Eddie” Harrant, Dunn, NC
- Francis T. “Jay” Jarvis, Armuchee, GA
- Don Mikko, Ellenwood, GA
- John Nixon, Bippus, IN
- Lester Roane, Street, MD
- Ronald L. Singer, M.S., Fort Worth, TX
- Russell Thomas, Roxboro, NC
- William (Bill) Tobin, Lake Anna, VA
- Eric Warren, Ph.D., Cordova, TN
- Robert S. White, Charleston, WV
- Josh Wright, Asheville, NC