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People v. Ross, 129 N.Y.S.3d 629 (Supreme Court, Bronx Counrt, NY) (slip op.)

Case (cite)
People v. Ross, 129 N.Y.S.3d 629 (Supreme Court, Bronx Counrt, NY) (slip op.)
New York
Type of proceeding
Type of claim
Type of claim (second claim)
Expert evidence ruling reversing or affirming on appeal:
What was the ruling?
Correct to Admit
Type of evidence at issue:
Firearms identification
Defense or Prosecution Expert
Name of expert(s) who were the subject of the ruling
Jennifer Lady
Summary of reasons for ruling
The court found the relevant scientific community under Frye to include not only Forensic scientists but also "researchers in scientific methodology and statistics" and to some extent psychologists. The court concluded that: "This broad community has no consensus on the more subjective findings and conclusions of toolmark examiners. The vague 'sufficient agreement' standard and the circular reasoning needed to arrive at a firearm identification has no acceptance in mainstream science," and that the language used may "mislead jurors."The court states that "pracitcal experience must have some relevance and value," and finds that "class characteristics" can be reliably testified about because "unquestionably firearms leave marks on shell casings and bullets when weapons are fired," and examiners are extensively trained to recognize these marks. However, the court holds that subclass characteristics can evolve over time and would ordinarily not by known to the examiner, and suffers from disagreement among mainstream scientists.
The jurisdiction’s standard for expert admissibility at the time – list all that apply: (Frye), (Daubert), (Post-2000 Rule 702), (Other)
Second standard
Did lower court hold a hearing
Names of prosecution expert(s) two testified at hearing
Lady, Todd Weller
Names of defense expert(s) who testified at hearing (or None).
Jonathan Fox; David Faigman and Nicholar Surich (scientific research methodology and study design); court called Dr. Heike Hofmann as expert on statistics to testify about error rates
Discussion of 2009 NAS Report (NAS2009)
Discussion of 2016 PCAST report (PCAST)
Discussion of error rates / reliability
Frye Ruling
Limiting testimony ruling
Language imposed by court to limit testimony
Ruling based in prior precedent / judicial notice
Daubert ruling emphasizing – which factors – (list 1-5)
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


It would be farcical to preclude experienced ballistics experts from rendering any opinion about known manufacturing marks. There is a consensus, or at least not all that much disagreement, to allow examiners to express an opinion on toolmarks that are class characteristics. The defendants’ challenge to all expert testimony on toolmarks is therefore rejected.




Courts must be wary when scientific evidence is offered to prove a defendant’s guilt. The problem of a microscopist putting expert conclusions before the jury is not solved by the opportunity to cross examine or present a countervailing expert on methodology. Experts enter upon the jury’s province, since the expert—and not the jury—draws conclusions from the facts. . . . The testimony of “sufficient agreement of a match” or even the language “consistent with” goes to the heart of the question of guilt.


Fortunately, evidence submitted at the hearing suggests positive change is coming. Research into 3D technology promises a potential for automatic analysis of the surface topographies of bullets, such that the current problems of subjectivity and quantifying the marks and impressions more precisely. (People’s Ex. 31, 36). As Dr. Hofmann observed, “[m]atching bullets is clearly not a one-step process, but rather a sequence of data analysis tasks each deserving attention. As there is no scientific standard in place at this point in time, our intent is to explain an approach to addressing these tasks, *918 while documenting all steps and providing all code so that other researchers and forensic scientists can reproduce and expand on our findings. Science may well eliminate the interpretation, guesswork and biases associated with visual forensic examinations.”


“Forensic scientists maintain that by examining toolmarks under a microscope, a trained examiner can determine whether there is “sufficient” agreement to reliably identify a particular *902 firearm as the source of the toolmarks. Researchers in traditional scientific disciplines– including study design and research methodology, statistics and psychology–are unified in their view that toolmark identification is just a practice in search of a science and is not reliable.”


“As a number of courts have pointed out that the AFTE standard is circular—an identification can be made upon sufficient agreement, and agreement is sufficient when an identification can be made.”


Relevant scienfic community: “The People adhere to the view that the relevant scientific community should be limited to forensic scientists and their established conclusions. Yet Frye demands an unbiased, objective review by those with no professional interest in its acceptance. . . . The professional standing and livelihood of forensic scientists depends on the validity of AFTE theory. See United States v. Tibbs, 2019 D.C. Super. LEXIS 9. Certainly this came across in the testimony of Mr. Weller, a professional consultant and frequent expert witness for the prosecution. The targeted use of AFTE theory by law enforcement investigators, under pressure and with potential for confirmation bias, limits the degree of intellectual rigor and detachment that counts as neutral scientific expertise.”


Most courts conclude that although the studies have flaws and the error rates are simply too hard to calculate, because of the rigor of examiner training and the assumption that error rates are low, some expert toolmark testimony should be permitted. See United States v. Johnson, 2019 WL 1130258. But a number of district courts hearing Daubert17 challenges have broadened the relevant **640 scientific community to take into account the contrasting views of mainstream researchers. Consequently, the scope of permissible expert toolmark testimony is narrowing overall.


Forensic scientists and AFTE themselves have not taken a head-in-the-sand attitude lately but appeared to recognize that toolmark identification, while time honored in the field and the courtroom, is under attack and must withstand scrutiny by other researchers. The People submitted numerous exhibits demonstrating that forensic science has picked up the pace and virtually raced to publish favorable studies. Where forensic science has fallen short, however, is that these validation efforts have been afflicted by fatally flawed study designs and subpar quantitative and qualitative measurements.