Sexton v. State, 93 S.W.3d 96 (Tex. Crim. App. 2002)

“The potential rate of error factor weighs in favor of exclusion. Crumley testified that this technique is one hundred percent accurate. Vincent DiMaio, author of one of the treatises on which Crumley relied, testified that he could not be one hundred percent accurate in matching two cartridge cases based on their magazine markings unless he had the actual magazine. The Court of Appeals found it significant that DiMaio’s interest in firearms identification was only a hobby. DiMaio, the Court of Appeals noted, did not qualify as a firearm and toolmark expert,5 therefore his opinion should not discount the reliability of Crumley’s assertion that the technique employed was one hundred percent accurate.
Crumley’s bare assertion is one that the available literature contradicts, however. The literature says that these marks may enable an examiner to connect cartridge cases with the same weapon. The only literature that explains what circumstances make it possible for an examiner to do so requires that the examiner possess knowledge of the manufacturing process of the tool surface and have the tool available for creating test toolmarks. In this case, the magazine or magazines that made the marks upon which Crumley based his identification were not found by the police. Therefore Crumley was not able to make test marks for comparison. Also, Crumley did not say whether he was familiar with the manufacturing process of the magazine or magazines that he said left identifiable marks on the live rounds and cartridge cases.”

 

 

 

 

 

 

 

 

 

U.S. v. Romero-Lobato, 379 F.Supp.3d 1111 (D. Nev. 2019)

“The cases surveyed by the Court indicate that some federal courts have recently become more hesitant to automatically accept expert testimony derived from the AFTE method. While no federal court (at least to the Court’s knowledge) has found the AFTE method to be unreliable under Daubert, several have placed limitations on the manner in which the expert is allowed to testify. The general consensus is that firearm examiners should not testify that their conclusions are infallible or not subject to any rate of error, nor should they arbitrarily give a statistical probability for the accuracy of their conclusions. Several courts have also prohibited a firearm examiner from asserting that a particular bullet or shell casing could only have been discharged from a particular gun to the exclusion of all other guns in the world. These restrictions are in accord with guidelines issued by the Department of Justice for its own federal firearm examiners which went into effect in January 2019. (ECF No. 51-8 at 4). But it is also important to note that the courts that imposed limitations on firearm and toolmark expert testimony were the exception rather than the rule.”

 

 

 

“While the Court is cognizant of the PCAST Report’s repeated criticisms regarding the lack of true black box tests, the Court declines to adopt such a strict requirement for which studies are proper and which are not. Daubert does not mandate such a prerequisite for a technique to satisfy its error rate element.”

 

” Federal Rule of Evidence 702 inherently allows for an expert with sufficient knowledge, experience, or training to testify about a particular subject matter. It does not impose a requirement that the expert must reach a conclusion via an objective set of criteria or that he be able to quantify his opinion with a statistical probability. Such requirements would, in most circumstances, exclude psychologists, physicians, and lawyers from testifying as expert witnesses. Of course, a litigant would be hard pressed to make a good faith argument that the methods used by mainstream medical and legal experts are unreliable under Daubert.”

 

While the CMS method has been peer reviewed, published in scientific journals, and tested, it is not routinely used by firearm examiners across the country. The lack of uniform adoption and the fact that Johnson does not use it as his primary method of identification means that the CMS method cannot, in the Court’s view, transform the subjective factor in the AFTE method to an objective one. The CMS method does, however, offer some objective validation to the AFTE Method.

 

Moreover, it is unclear if the PCAST Report would even constitute criticism from the “relevant community” because the committee behind the report did not include any members of the forensic ballistics community

 

The Court also notes that the defense has not cited to a single case where a federal court has completely prohibited firearms identification testimony on the basis that it fails the Daubert reliability analysis. The lack of such authority indicates to the Court that defendant’s request to exclude Johnson’s testimony wholesale is unprecedented, and when such a request is made, a defendant must make a remarkable argument supported by remarkable evidence. Defendant has not done so here.

 

NOTE: Interestingly, this case has a lengthy discussion at the beginning about courts limiting expert testimony, but does not mention limiting testimony in this case.

 

People v. Cowan, 236 P.3d 1074 (Cal. 2010)

Method used by expert: Laskowski testified that in 1984 he had excluded the Colt pistol as the source of the bullets recovered from Clifford’s body based on a comparison of those bullets with test-fired bullets. A few weeks before trial, however, Detective Christopherson had informed him that the inside of the barrel had been altered. Laskowski reexamined the gun and determined that the land impressions near the crown of the barrel had been damaged to such an extent that comparison with test-fired bullets was impossible. Laskowski therefore made a cast of the interior of the barrel using Mikrosil, a silicone rubber compound routinely used in the casting of tool marks. He then compared the markings on the cast that had been recorded from the inside of the barrel with the two bullets recovered from Clifford’s body, and determined the bullets had been fired from the Colt pistol.

 

 

 

On cross-examination, Laskowski admitted that neither he nor any other ballistics expert he was aware of had ever testified in court regarding ballistics comparisons using Mikrosil casting. However, at least a dozen or more experts he had spoken with told him that the method was “acceptable.” Moreover, he explained, the technique was not new, because “the recording of tool marks with an elastomeric material has been done,” and firearms examination was essentially a subset of tool mark comparison.

 

At the Evidence Code section 402 hearing and at trial, Laskowski explained in detail the process he had used to create the barrel cast and compare it to the bullets recovered from Clifford Merck’s body. Laskowski showed photographs of the gun, the barrel cast, the test-fired bullets and the recovered bullets to the jury and identified the points of similarity he found between the cast and the recovered bullets. Although there was some dispute about whether the method Laskowski used produced a cast of the barrel “without tampering or alteration” due to possible bubbling or shrinkage of the Mikrosil, that possibility was fully explored on cross-examination and the jury had the opportunity to weigh its effect on the validity of Laskowski’s conclusions. Thus, here too there was no need to debate the reliability of the method under the standards of Kelly.

 

Kelly rule: The Kelly rule provides that the “admissibility of expert testimony based on a ‘new scientific technique’ requires proof of its reliability—i.e., that the technique is ‘ “sufficiently established to have gained general acceptance in the particular field to which it belongs.” ’