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People v. Azcona, 272 Cal.Rptr.3d 471 (Ct. App. Cal. 2020)

Case (cite)
People v. Azcona, 272 Cal.Rptr.3d 471 (Ct. App. Cal. 2020)
Type of proceeding
Type of claim
Type of claim (second claim)
Expert evidence ruling reversing or affirming on appeal:
What was the ruling?
Error to Admit; Remand
Type of evidence at issue:
Firearms identification
Defense or Prosecution Expert
Name of expert(s) who were the subject of the ruling
Summary of reasons for ruling
Defendant argues that firearms identification is not reliable. The California court uses the Kelly (Frye) standard that it does not need to be reliable, only generally accepted by the relevant community. The defendant had his own expert testify about firearms identifcation and about the NAS 2008, 2009, and PCAST reports. However, the court held it "cannot find the method categorically inadmissible here because defendant did not meet his burden to show that a clear majority of the relevant scientific community no longer accepts the method as reliable. Indeed, defendant neither established what the relevant scientific community is, nor that a clear majority of that community now rejects ballistics comparison as unreliable. Defendant focused in the trial court, as he does here, on attacking the reliability of the method itself. But it is not for the court to determine whether the method is reliable (in contrast to what a federal court would do under the Daubert standard). The necessary inquiry under Kelly is whether most of the relevant scientific community thinks it is."
The jurisdiction’s standard for expert admissibility at the time – list all that apply: (Frye), (Daubert), (Post-2000 Rule 702), (Other)
Rule 801
Second standard
Did lower court hold a hearing
Names of prosecution expert(s) two testified at hearing
Does not say
Names of defense expert(s) who testified at hearing (or None).
Does not name the expert
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


The expert’s explanation of his conclusions: “He explained: “I need to see six individual marks in a row [ ] to meet my identification criteria. That’s based on the fact that nobody’s ever seen that many by random chance. [¶] We’ve done numerous studies on the subject trying to see what can happen by random chance, and that’s much more than can ever happen by random chance. [¶] So if you see these marks and all your class characteristics are the same and you can identify the source of the marks, it is possible to say they were fired from the same gun. And the thing that’s good to add on now days is not just that they were fired from the same gun, but to the practical exclusion of all other guns.””




“Expert testimony based on the application of a scientific technique is admissible in California if the technique is generally accepted in the pertinent scientific community. . . . That test has been criticized as essentially delegating admissibility to scientists without a judge directly confronting the reliability of the evidence. . . . But the Supreme Court has continued to endorse the Kelly standard, reasoning that “it may be preferable to let admissibility questions regarding new scientific techniques be settled by those persons most qualified to assess their validity.” ”


On using Kelly (Frye) over Daubert: “The California approach is a departure from the test applied to novel scientific evidence in federal courts. Rather than admitting the evidence based on a general consensus about its reliability, federal courts, under Daubert v. Merrell Dow Pharm., Inc. (1993) 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469, conduct a broader inquiry which allows the court to exercise its own judgment about whether the technique used is reliable. . . . In contrast, “[u]nder the Kelly test, the admissibility of evidence obtained by use of a scientific technique does not depend upon proof to the satisfaction of a court that the technique is scientifically reliable or valid. Because courts are ill suited to make such determinations, admissibility depends upon whether the technique is generally accepted as reliable in the relevant scientific community.” . . . As a result of the difference in state versus federal approaches, the federal authorities cited by defendant are of limited value here because they focus on directly examining the reliability of toolmark comparison methods”


Defendant presented legitimate criticism from credible sources: scientific reports commissioned by the federal government, and testimony by a research scientist. That evidence undermines the reliability of the method and casts some doubt on the prosecution expert’s conclusion that particular bullet casings came from the same firearm. The information was therefore relevant and important for the jury to consider in assessing the expert testimony. And the jury was afforded that opportunity through defense counsel’s extensive cross-examination of the prosecution expert regarding those very criticisms of the method. The expert acknowledged he was aware of the reports but disagreed with them, and thought the authors were not qualified to conduct firearms analysis. Criticism of the method from credible sources surely affects the persuasive value of the evidence, but it does not equate to what defendant needed to show to render the firearms expert’s testimony inadmissible: that the method is no longer accepted by a clear majority of the relevant scientific community.