Post PCAST: Washington D.C. High Court Won't Tolerate No-doubt Testimony Matching a Bullet to a Single Gun

In an opinion relying in part on the PCAST Report on feature-comparison evidence, the District of Columbia's highest court discussed limits on the testimony a firearms-toolmark examiner can give. But it did not get very far. An earlier opinion in Williams v. United States, 130 A.3d 343 (D.C. 2016), determined that the admission of some extreme testimony (described below) was not plain error. In Williams v. United States, 210 A.3d 734 (D.C. 2019) (Williams II), the Court of Appeals revisited the plain-error question in light of later rulings decided before sentencing. It concluded that even though entertaining the opinion testimony was "error" and the error was "plain," the "plain error" exception to the rule against reversing a conviction on the basis of unobjected-to testimony did not justify reversal. (I know, that is a convoluted sentence, but the law on the plain-error exception to the need for a contemporaneous objection is convoluted.)

At trial,

[T]he examiner opined that “these three bullets were fired from this firearm.” On redirect, when asked whether there was “any doubt in [his] mind” that the bullets recovered from Mr. Kang's SUV were fired from the gun found in Mr. Williams's bedroom, the examiner responded, “[n]o, sir.” The examiner elaborated that “[t]hese three bullets were identified as being fired out of Exhibit No. 58. And it doesn't matter how many firearms Hi[-]Point made. Those markings are unique to that gun and that gun only.” The examiner then restated his unequivocal opinion: “Item Number 58 fired these three bullets.”

(Citations omitted). On the petition for rehearing that generated the Williams II opinion, the government relied on a footnote in one of these cases, Gardner v. United States, 140 A.3d 1172 (D.C. 2016). The note in Gardner stated that the holding was “limited in that it allows toolmark experts to offer an opinion that a bullet or shell casing was fired by a particular firearm, but it does not permit them to do so with absolute or 100% certainty.” 140 A.3d at 1184 n.19. The government argued in Williams II that "this footnote authorized opinion testimony identifying a specific bullet as having been fired by a specific gun."

Justice Catharine Easterly's opinion for the court found this interpretation of the footnote "difficult to square with the above-the-line holding that the trial court 'had erred' by admitting the examiner's 'unqualified opinion,' that the 'the silver gun was the murder weapon.'" Id. at 1184. The opinion added that

Moreover, the publication post Gardner of another federal government report—President's Council of Advisors on Science and Technology (“PCAST”), Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods (Sept. 2016), ... reiterates toolmark and firearms examiners do not currently have a basis to give opinion testimony that matches a specific bullet to a specific gun and that such testimony should not be admitted without a verifiable error rate does not support the government's argument that only express statements of certainty should be prohibited.

Nonetheless, the opinion did not "resolve the ambiguity of Gardner's footnote because "in this case ... the firearms and toolmark examiner not only testified ... that a specific bullet could be matched to a specific gun, but also that he did not have 'any doubt' about his conclusion." (Footnote omitted.) In the end, after emphasizing that the no-doubt-specific-source testimony "was error," and "the error is plain," the court only held that the plain-error exception to the rule against reversing on the basis of evidence that was not the subject of a contemporaneous objection did not apply. It did not apply because, considering "the government['s] powerful circumstantial case" in other respoects, "Mr. Williams ... cannot show a reasonable probability of a different result absent this error."

Reading between the lines, it appears that Justice Easterly was unable to convince the other two panel members to explicitly adopt (in dictum) the procedure PCAST recommended for source attributions -- a categorical conclusion accompanied by the upper bound of an estimated rate of Type I error as seen in so-called black-box experiments (or something similar). She wrote separately that the Gardner footnote "can only logically be understood in one way: as an acknowledgment that the government might be able to present expert opinion testimony that a specific bullet was fired by a specific a gun if the examiner could reliably qualify his pattern-matching opinion—i.e., if he can provide a verifiable error rate." To which Senior Judge Frank Nebeker replied in his separate opinion: "This is not a case in which to resolve the knotty question of to what degree of certainty, or not, an expert's opinion is admissible as to a particular fact." 1/

NOTE

1. Whether any source-attribution opinion -- with or without some initial qualification as to the degree of certainty -- is necessary or desirable is a further question, even more removed from what Judge Nebeker loosely called a "harmless error judgment." (The harmless-error doctrine is a little different from the plain-error doctrine.)

Index to comments and cases on the PCAST report