Last month, in Gardner v. United States, Nos. 11–CF–557, 14–CO–832, 2016 WL 3474642 (D.C. June 23, 2016), the court declared that "in this jurisdiction a firearms and toolmark expert may not give an unqualified opinion, or testify with absolute or 100% certainty, that based on ballistics pattern comparison matching a fatal shot was fired from one firearm, to the exclusion of all other firearms."
The defendant, Eric Gardner, was on trial (for a second time) for shooting Andrew Kamara, a taxicab driver. Part of the case against him consisted of expert testimony about bullet cartridges associated with the shooting. Defense counsel wanted the trial court to rule that "what is appropriate is for the expert to testify specifically in this case that the bullet that was recovered from the decedent is consistent with ... one of the pistols that he was given to examine but not state that it was ... [with] any scientific certainty." The trial court replied that he would let the expert "state his conclusions—his reasonable conclusions and you can impeach him up and down, if you want."
And so the government's expert, Lyndon Watkins, "stated that the silver gun was the murder weapon." Furthermore, he
The Court of Appeals noted that despite the long history of judicial acceptance of bullet-matching testimony, "[b]eginning around 2008, however, questions about pattern matching generally, and bullet pattern matching specifically, surfaced in the scientific community." Although it cited only law review articles for this assessment, it then pointed to reports of the National Research Council and the fact that "some jurisdictions began to limit the scope of a ballistics expert's testimony."
After noting that the issue had not been resolved in Williams and an earlier case on the subject, the court announced that
Apparently, the government did not directly defend its prosecutor’s use of "that’s the gun" testimony, but contended that "any possible error in the admission of Watkins' testimony without 'qualification' was harmless."
Where this leaves the law of the District of Columbia is unclear. Apparently, error can arise short of the tag phrase "to the exclusion of all other guns in the world," but what "qualification" of the testimony that "This is the gun!" is required? Defense counsel maintained "that the error in admitting Mr. Watkins' unqualified opinion was not harmless because . . . ‘the difference between whether the silver gun was definitely the murder weapon or whether it was simply believed by the ballistician to be the murder weapon may well have affected the jury's deliberations.’" But it hardly seems satisfactory to draw the line between the statement of an expert toolmark examiner that (1) "This is the gun that fired the bullet" and (2) “"his is the gun that, in my opinion as an expert trained and experienced in these matters, fired the bullet."
In earlier cases, the government represented that its policy was to permit testimony that to "a reasonable scientific certainty," this is the gun. That is a "qualification," I suppose, but it is no better than the "unqualified" one in resolving "questions about pattern matching . . . in the scientific community."
Of course, the beauty of the common law is that courts need not (and cannot) definitively resolve the myriad of factual patterns not yet presented, but the absence of any real explanation in Gardner of why a positive identification of a gun from expended bullets is unacceptable means that the opinion leaves a wide range of "qualified" testimony up in the air.