Skip to content

United States v. Harris, 2020 WL 6488714 (D.D.C. 2020)

Case (cite)
United States v. Harris, 2020 WL 6488714 (D.D.C. 2020)
Type of proceeding
Type of claim
Expert evidence ruling reversing or affirming on appeal:
What was the ruling?
N/A; Trial court
Type of evidence at issue:
Firearms identification
Defense or Prosecution Expert
Name of expert(s) who were the subject of the ruling
Chris Monturo
Summary of reasons for ruling
Court analyzes all 5 Daubert factors and holds that the method is reliable. The court provides recent evidence countering the PCAST report including advances in technology since the report's publication, new studies conducted showing low false-positive error rates, the AFTE journal is scientifically sound and other disciplines have also published firearms identification studies. However, the court found that the Daubert factor concerning standards was not met, saying, "even in contrast to other subjective disciplines such as fingerprint analysis, firearm toolmark identification does not provide objective standards even as a quality control measure, such as a baseline to trigger further verification."
The jurisdiction’s standard for expert admissibility at the time – list all that apply: (Frye), (Daubert), (Post-2000 Rule 702), (Other)
Daubert; 702
Did lower court hold a hearing
N/A (this court held one)
Names of prosecution expert(s) two testified at hearing
Todd Weller
Names of defense expert(s) who testified at hearing (or None).
Discussion of 2009 NAS Report (NAS2009) or PCAST report (PCAST)
Discussion of error rates / reliability
Frye Ruling
Limiting testimony ruling
Language imposed by court to limit testimony
Limitations were already agreed to by the government, including "will not use terms such as “match,” he will “not state his expert opinion with any level of statistical certainty,” and he will not use the phrases when giving his opinion of “to the exclusion of all other firearms” or “to a reasonable degree of scientific certainty.” The court did not add more
Ruling based in prior precedent / judicial notice
Daubert ruling emphasizing – which factors – (list 1-5)
(1), (2), (3), (4), (5)
Ruling on qualifications of expert
Ruling on 702(a) – the expert will help / assist the jury
Ruling on 702(b) – the testimony is based on sufficient facts or data
Ruling on 702(c) – the testimony is the product of reliable principles and methods
Ruling on 702(d) – reliable application of principles and methods to the facts of the case


“The Court is generally convinced by the Government’s arguments and ample citations to case law that the 2008 Ballistic Imaging Report and the 2009 National Academy of Science Report are both “outdated by over a decade” due to intervening scientific studies and as a result have been repeatedly rejected by courts as a proper basis to exclude firearm and toolmark identification testimony.”


his conclusion has only been further strengthened in recent years due to advances in three-dimensional imaging technology, which has allowed the field to interrogate the process and sources of “subjectivity” behind firearm and toolmark examiners’ conclusions.


“Setting aside for the moment the utility of this “black-box” requirement—which goes beyond what is required by Rule 702—the Government has provided to the Court three recent scientific studies that meet the PCAST’s black-box model requirements and demonstrate the reliability of the firearm and toolmark identification method. These include one of the tests administered during the Heat Map Study detailed above, see Weller II at 16 n. 84, along with another recent black box study testing the identification of fired casings, which resulted in a .433% false positive error rate from three errors among 693 total comparisons. See Lilien et al., Results of the 3D Virtual Comparison Microscopy Error Rate (VCMER) Study for Firearm Forensics, J. of Forensic Sci. Oct. 1, 2020 (“Lilien Study”) at 1, ECF No. 41. A third post-PCAST Report study also followed the PCAST recommended black-box model and found that of 1512 possible identifications tested, firearms examiners correctly identified 1508 casings to the firearm from which the casing was fired. Keisler et al., Isolated Pairs Research Study, Ass’n of Firearm and Tool Mark Examiners J. 56, 58 (2018) (“Keisler Study”), ECF No. 33-9; see also Evid. Hr’g Tr. 65:3-11. This evidence indicates that even under the PCAST’s stringent black-box only criteria, firearm and toolmark identification can be tested and reasonably assessed for reliability”


“The entire process of reaching a conclusion regarding the “sufficient agreement in individual characteristics” is one that relies wholly on the examiner’s judgment, without any underlying numerical standards or guideposts to direct an examiner’s conclusion. . . .And as Mr. Weller testified, even in contrast to other subjective disciplines such as fingerprint analysis, firearm toolmark identification does not provide objective standards even as a quality control measure, such as a baseline to trigger further verification. . . . While Mr. Monturo’s additional use of “basic scientific standards” through taking contemporaneous notes, documenting his comparison with photographs, and the use of a second reviewer for verification surely assist in maintaining reliable results, without more the Court cannot conclude this Daubert factor is met.”