Saturday, January 18, 2020

A Fourth Model of Law Enforcement Access to DNA Databases

First there were DNA databases of four or five RFLP VNTR measurements obtained by gel electrophoresis of the DNA fragments of convicted offenders. These were soon superseded by much larger databases for convicted-offenders (and later, arrestees) comprised of a larger number of STRs determined with capillary electrophoresis. The individuals supplying the DNA analyzed in these limited ways had no choice in the matter. Statutes compelled them to submit to DNA sampling, and only law enforcement authorities had access to these special-purpose, government-run databases.

In recent years, the potential for private databases to generate investigative leads through trawling (without individualized suspicion or probable cause) has begun to be exploited. Millions of SNP-based records reside on the servers of recreational genetics companies that process saliva samples with SNP arrays that determine the alleles present at hundreds of thousands of SNP loci. The customers of each direct-to-consumer (DTC) testing company can learn if other participating customers of that company have large blocks of DNA in common -- a situation indicative of a family relationship. (Other tests for relatedness in the private databases are also possible, but the haploblock-matching procedure has been the most productive for criminal investigations because it casts a wider net.) In addition, over a million samples reside in the voluntary private database known as GEDmatch, which enables genealogy enthusiasts to share their personal SNP-array data.

SNP-array testing does not work well with crime-scene DNA samples that contain mixtures of DNA from several individuals, that are severely limited in quantity, or that are degraded. However, an alternative technology, known as massively parallel, or next generation sequencing (MPS or NGS), can generate genomic data from challenging samples, and the sequence data can be culled to supply the SNP-array data that DTC companies would have provided had the source of the DNA evidence from the crime-scene sent a saliva sample in to one of these companies. Armed with such a data file, police who are able to access a DTC or GEDmatch-type database can look for potential relatives. By turning to these individuals (or public records about the families), police sometimes can find a suspect who merits further investigation.

Many DTC customers who did not realize their DNA might lead police to their relatives (known or unknown to them) have found this kind of forensic genomic genealogy (FGG) profoundly disturbing, at least when it was not something they had explicitly signed up for. Others have evinced less concern. The private database operators have responded with different policies. GEDmatch presumes that users object, but allows them to indicate their willingness to have their data used in law-enforcement trawls. Another possible response is an opt-out policy, in which the presumption is that individuals are not opposed to this use of their data. Yet another policy is that the database is always open to law enforcement, just as it is to curious individuals. Finally, the database could be completely closed to law-enforcement trawling (without judicial approval based on a showing of individualized cause).

In short, there are three main models of law enforcement access: (1) the government-run, law-enforcement-only database; (2) the private other-purpose, opt-in database; and (3) the private other-purpose, opt-out database. However, a fourth model is emerging -- a privately run law-enforcement-only database.

An article from the information service GenomeWeb reports on the plans of Othram, which bills itself as "the first technology company to apply all the power of modern sequencing and genomics to forensics" so as to secure "justice through genomics." The article includes a number of interesting statements from the company's CEO, David Mittelman. GenomeWeb explains that
Othram ... introduced to solicit users of consumer genomics services to upload their data for the expressed desire to help law enforcement solve cold cases.

"Family Tree DNA is doing the opt-out model [with regards to law enforcement], GEDmatch is doing opt-in," said ... Mittelman. "I thought there should be another model," he said. "Since we do nothing but law enforcement, there is nothing to opt out of."

Mittelman, a former CSO at Family Tree DNA parent Gene by Gene ... said "I have enjoyed the consumer genetics and genealogy side, and I certainly enjoyed the medical side, but I saw the forensics market as a market that was underserved and could benefit from the technology that has been widely used and embedded in consumer and medical testing," he said. "It made sense to bring that technology over."

Mittelman credited the developments in the market with both the success of consumer genomics as well as advancements in next-generation sequencing technology. By some estimates, 30 million people have taken an array-based consumer test to date. Meantime, the drop in the price of sequencing, plus ongoing innovation in the field, means that it is now possible to perform whole-genome sequencing of highly degraded samples from crime scenes and then scour large databases to find genetic relatives, constructing genealogies to identify victims or perpetrators.
"In 2019, sequencing failed to penetrate the consumer market," said Mittelman. "But forensics is an interesting market where sequencing is superior to arrays," he said. "It is not just that sequencing gives you more information, in a lot of cases it's the only way to get information," he added.
Othram's approach is called Forensic Grade Genome Sequencing. According to Mittelman, array technology has a "high failure rate" when it comes to forensic samples, making sequencing the go-to technology when it comes to working with these kinds of samples.

"You really need special methods," said Mittelman. "We have developed proprietary methods to adapt the worst kinds of DNA to sequencing," he added. "I think in the long term forensics will only work with sequencing, while for consumer, arrays are good enough."

Othram has not yet published on its techniques, but eventually aims to do so, Mittelman said. While the company hones its sequencing capabilities, it is also hoping more customers of consumer services will be moved to upload their data to He noted that only a small percentage of those tested have elected to upload data to GEDmatch, meaning the potential exists to grow a new database of a different set of users interested in helping law enforcement.

"Rather than target a small number of people who are genealogy power users, and ask them to help solve crime instead, it seemed to me that you could approach the 30 million who have tested and tell them if you have tested and feel like getting involved, this is how you do it," said Mittelman. "You don't have to be a power user in genealogy to make a difference in crime solving."
Whether will attain the critical mass to be a useful investigative database is not guaranteed, so it is not clear that the data donors will be "making a difference in crime solving." Buut even if the database remains small, Othram can market its FGG service as offering the police agency access to a exclusive database. In a seeming excess of enthusiasm about finding "the most distantly related individuals," the website states that
We are all genetically related to one-another [sic]. Genetic genealogy uses DNA information in combination with genealogical and historical records to establish relationships between even the most distantly related individuals. This is a substantial improvement in human identification capability from current forensic testing methods that enable exact or near exact matches. When you contribute your DNA data, you help identify victims, missing persons, and perpetrators of crimes — even if you are a distant genetic relative.


Justin Petrone, Forensic Genomics Market Advances Due to Consumer Databases, Technology Innovation, genomeweb, Jan. 9, 2020,

Friday, January 17, 2020

What Are the Law Enforcement Implications of the GEDmatch Buyout?

GEDmatch is a free genetic genealogy database that allows people to upload their genomic data from direct-to-consumer (DTC) testing services such as 23andMe, Ancestry, MyHeritage, and Family Tree DNA. It permits cross-company searches for possible relatives among those who elect to participate. To date, roughly 1.3 million people have uploaded their SNP array data to the service, and GEDmatch continues to add about 1,000 people daily. 1/ Scientists and genealogists working for law enforcement agencies have been able to locate the source of DNA evidence from unsolved crimes by discovering a possible relative who supplied his or her data to public kinship searching in GEDmatch. The result has been fluctuating policies with respect to police use of GEDmatch's haploblock-matching software and uploaded data to produce some leads. 2/

Last month (19 Dec, 2019), GEDmatch's founder sent the following email to its registered users:
To GEDmatch users,

As you may know, on December 9 we shared the news that GEDmatch has been purchased by Verogen, Inc., a forensic genomics company whose focus is human ID. This sale took place only because I know it is a big step forward for GEDmatch, its users, and the genetic genealogical community. Since the announcement, there has been speculation about a number of things, much of it unfounded.

There has been concern that law enforcement will have greater access to GEDmatch user information. The opposite is true. Verogen has firmly and repeatedly stated that it will fight all unauthorized law enforcement use and any warrants that may be issued. This is a stronger position than GEDmatch was previously able to implement.

...It has been reported on social media that there is a mass exodus of kits from the GEDmatch database. There has been a temporary drop in the database size only because privacy policies in place in the various countries where our users reside require citizens to specifically approve the transfer of their data to Verogen. As users grant permission, that data will again be visible on the site. We are proactively reaching out to these users to encourage them to consent to the transfer.

... Verogen recognizes that law enforcement use of genetic genealogy is here to stay and is in a better position to prevent abuses and protect privacy than GEDmatch ever could have done on its own.

Bottom line: I am thrilled that the ideal company has purchased GEDmatch. The baby I created will now mature for the benefit of all involved. If anyone has any doubts, I may be reached at I will do my best to personally respond to all concerns.

Curtis Rogers
Verogen's acquisition has produced angst among observers who worry that the company will exploit it for police purposes. The observation that Verogen "caters to law enforcement" 3/ has become a media meme. Verogen is a 2017 spin-off from Illumina, Inc., the San Diego Company that pioneered and acquisitioned its way to cheap DNA sequencing machinery for research and clinical applications. Illumina also sells the arrays that the DTC companies use, but that technology is not suitable for most crime-scene samples. Verogen's website proudly announces that "Verogen serves those who pursue the truth" by being "the world’s first sequencing company solely dedicated to forensic science. ... Powered by Illumina technology and free of legacy method allegiance, we are uniquely positioned to support forensic labs with innovative solutions purpose-built for the challenges of DNA identification."

The purpose-built solutions free of legacy method allegiance that Verogen now markets use Illumina's technology for massively parallel sequencing by synthesis that culminates in traditional autosomal forensic STR data and much more genomic data.It is superior to capillary electrophoresis, especially for small, degraded, and mixed DNA samples. Competitors market other packages of MPS devices, reagents, and software to forensic laboratories. 4/

How Verogen's ownership will affect police access to GEDmatch is not clear. No doubt, Verogen would like the police to use the database, but it cannot afford to alienate the genealogy enthusiasts who send in their SNP array data. It can provide materials and software that would help forensic laboratories who use sequencing technology to generate the SNP data in the format for trawling GEDmatch for haploblock matches. Indeed, Verogen has a "forensic genetic genealogy product in development for forensic laboratories [that] will actually provide more privacy protection for users of GEDmatch, as the test is focused on kinship analysis for forensic purposes." 5/ But I am curious as to how this purpose-built product will provide more privacy protection than occurs with kinship matching for private purposes.

  1. Justin Petrone, Forensic Genomics Market Advances Due to Consumer Databases, genomeweb, Jan 9, 2020,
  2. Police Genetic Genealogy at GEDmatch: Is Opt-in the Best Policy?, Forensic Sci., Stat. & L., Sept. 21, 2019,
  3. Heather Murphy,  What You’re Unwrapping When You Get a DNA Test for Christmas, N.Y. Times, Dec. 22, 2019 ("The new owner, Verogen, said that it would actively fight future search warrants and that users can still opt out of helping police. But Verogen is also a company that has built its business, so far, on catering to law enforcement.").
  4. Brigitte Bruijns, Roald Tiggelaar & Han Gardeniers, Massively Parallel Sequencing Techniques for Forensics: A Review, 39 Electrophoresis 2642-2654 (2018),
  5. Petrone, supra note 1.

Wednesday, January 15, 2020

OSAC-approved Testimony

According to the charter of the Department of Commerce's Organization of Scientific Area Committees for Forensic Science, better known as OSAC (but not to be confused with the Department of State's Overseas Security Advisory Council, also known as OSAC), "[t]he aims of the OSAC are to:
  • populate the OSAC Registry of Standards
  • promote the use of OSAC-endorsed standards by the forensic community, accreditation and certification bodies, and by the legal system
  • provide insight on each forensic science discipline’s research and measurement standard needs
  • enlist stakeholder involvement from a broad community; and to [sic]
  • establish and maintain working relationships with other similar organizations. 1/
OSAC is not a regulatory agency, and it does not review the work of forensic science laboratories or practitioners. Yet one court thought otherwise. In United States v. Lang, 2/ the defendant moved to exclude testimony from "the Government's firearms and toolmark expert—M.L. Cooper." The government wanted "Mr. Cooper ... to testify about what latent prints and DNA are and the factors that influence whether a latent print or DNA are left on a surface." Evidently, the point of the testimony was to explain the absence of fingerprint and DNA evidence in the case because of "the difficulty in obtaining latent prints and DNA from ammunition and the low rate at which such types of trace evidence are recovered."

Senior Judge Raymond L. Finch of the District Court of the Virgin Islands (formerly the court's Chief Judge) denied the motion. His unreported opinion on his pretrial ruling states that
On direct examination, Mr. Cooper testified that he reviewed a Crime Scene Evidence Report prepared by VIPD Officer Don Peter, photographs of the five buckshot shotgun shells recovered from Defendant's apartment, and photographs of the black garbage bag that contained the shells. He also testified that he confirmed his resulting opinion with OSAC (emphasis added).
This was not all that Mr. Cooper, and hence the court, had to say about OSAC. Judge Finch wrote that "Mr. Cooper is currently a member of the Association of Firearms and Toolmark Examiners—an organization that according to Mr. Cooper deals with the recovery of trace evidence—and maintains contact with the Organization of Scientific Area Committees ('OSAC')" (emphasis added). The nature of Mr. Cooper's "contact" with OSAC--or is it AFTE's "contact"--was left unstated, but the court thought it was important enough to add the footnote that "OSAC coordinates the 'development of standards and guidelines for the forensic science community to improve quality and consistency of work in the forensic science community.'"

Relying on an OSAC-approved standard for an opinion is one thing. But there are no standards on how to ascertain from a "review of the Crime Scene Evidence Report and photographs" that police would not be expected to recover a latent fingerprint or an adequate quantity of DNA to analyze, and being in "contact with" OSAC does not tell the court anything about the expertise of a witness or an organization.

Other parts of the opinion are more comprehensible (but not necessarily correct). The court wrote that the testimony "satisfies the reliability test under Daubert" just because it "will be based upon his more than thirty years of experience working in the field of forensic science." Experience can be a good thing, but it is not the scientific validity discussed in Daubert. More plausibly, the court moved away from its equation of experience to science. It stated that Mr. Cooper's methodology did not have to satisfy Daubert after all. "Rather than [applying] a methodology that satisfies the requirements of Daubert," Mr. Cooper would do little more than recount his personal experience with "the recovery of trace evidence" That much, the court insisted, "is entirely appropriate under Rule 702. See United States v. McNeil, 2010 U.S. Dist. LEXIS 290, at *8, 2010 WL 834667 (M.D. Pa. Jan. 5, 2010) ('To the extent that the expert has knowledge of the frequency of firearms without latent prints, the expert [can] testify to that knowledge.')."

  1. OSAC Charter and Bylaws, Sept. 26, 2019, Version 1.6.
  2. Crim. Action No. 2015-0013, 2016 WL 1734087 (D. V. I., Apr. 28, 2016).

Saturday, November 30, 2019

An Opinion on Historical Cell Site Location Evidence (with an Peculiar Explanation of Rule 702)

In United States v. Medley, 312 F.Supp.3d 493 (D. Md. 2018), an FBI agent prepared charts "showing the geographic layout of the various cell towers to which [Jovon] Medley's phone supposedly connected at the time and date of [a] carjacking." United States District Judge Paul W. Grimm overruled Medley's objection to these charts and testimony about them, but he also directed the expert to limit his testimony so as to avoid "reliability" concerns. This limiting technique is becoming increasingly popular for forensic science testimony that clearly has some probative value but is not as "scientific" as one might hope. 1/

Citing an opinion from the Court of Appeals for the Seventh Circuit, Judge Grimm noted that "[c]uriously, despite the frequent admission of historical cell site location evidence by trial courts in criminal cases, '[n]o federal court of appeals has yet said authoritatively that historical cell-site analysis is admissible to prove the location of a cell phone user.'" He added that "the Circuit Courts that have considered admissibility of this evidence have split in their assessment of its reliability, and consequent admissibility." This split, as described in Medley, seems to emanate from an unpublished opinion of the Sixth Circuit in United States v. Reynolds, 626 Fed.Appx. 610, 614–15 (6th Cir. 2015),

The Reynolds court did not exclude testimony linking a cellphone to a location, for the government only used the cell tower records to rule out the presence of the phone in certain areas. But the Reynolds court was unimpressed with the argument that "historical cell site location analysis was reliable because it had been tested and accepted by the law enforcement community" and "that the methodology had been tested successfully over a thousand times in locating suspects with historical cell site tracking data." The court of appeals disdainfully wrote that:
This claim appears to be precisely the sort of “ipse dixit of the expert” testimony that should raise a gatekeeper's suspicion. While being successfully employed “1000 times” may sound impressive, the claim is not subject to independent peer review and fails to establish an error rate with which to assess reliability because there was no information on how many times the technique was employed unsuccessfully.
After a digression on whether or when cell site location evidence could be presented by a lay witness (Judge Grimm acknowledged the "impressive credentials and qualifications" of the witness to testify as an expert), the opinion equated Rule 702's "reliability" requirements to Rule 401's definition of relevance:
[T]he essence of Rule 702 is to avoid misleading the jury with unreliable evidence (which, by its very nature, is irrelevant, because unreliable evidence has no tendency to make a fact that is of consequence to the litigation more probable than it would be without the evidence, and irrelevant evidence fails to be helpful to a jury). Opinions that are solidly grounded in the facts of a particular case, employ reliable methodology or principles, have passed scrutiny by other experts in the same field, and which were reached by strict adherence to established standards and procedures are helpful. Those that are not amount to nothing more than scientific or technical guesses.
But reliability falls on a continuum. "Helpful" as used in Rule 702 is by not a simple corollary of the definition of relevance as the tendency to make a fact more probable. Expertise encompasses more than just two states--the very secure and the useless. Probative but imperfect information fills a middle range, and the relevance requirement (in Rules 401 and 402) does not bar evidence in this zone. "Guesses" by someone who is good at guessing are relevant--they alter the subjective probability of the contested fact. But even shrewd guesses may be excluded under Rule 702 if and when they are dressed up as scientific facts or impeccable wisdom. Moreover, Rule 403, which requires that prejudicial effect not substantially outweigh probative value, also supports such exclusion.

The end result in Medley can best be  understood in this light. The inferences from the cell tower data, Judge Grimm concluded, must be limited to "general location" and must include "a candid explanation of the accuracy of the particular location method used, which must, by necessity, include its limits as well as strengths." At that point, it becomes probative and helpful enough to satisfy rules 403 and 702.

Of course, how to explain "accuracy" when a "mathematical error rate has not been calculated" remains something of a puzzle, but Judge Grimm announced that
While I will allow the Government to elicit the opinion from SA [Special Agent] Fennern that the location of the defendant's cell phone was “consistent with” the location of the crime scene at the time of the carjacking, he may not do so until after he has fully explained during direct examination the inherent limitations of the accuracy of his location evidence—namely, the phone can only be placed in the general area of the cell tower sector that it connected to near the time of the carjacking, and that it cannot be placed any more specifically within that sector.
This approach reflects the judgment that more definite inferences from cell tower records would not be sufficiently reliable or that such testimony would not be worth the time it might take for a battle over the more powerful assertions. At the same time, the court deemed "general location" testimony with  disclaimers up front as sufficiently probative even if it provokes an extensive cross-examination. Indeed, the court slipped in the suggestion that the defense could use "learned treatises" in its cross-examination.


1. In an unreported ruling from the bench in Medley, Judge Grimm also followed a middle path for firearms-toolmark testimony, limiting the examiner to "consistent with" testimony. See United States v. Johnson, No. (S5) 16 Cr. 281 (PGG), 2019 WL 1130258, at *20 (S.D.N.Y. Mar. 11, 2019) (declining to do the same; discussed at

Sunday, November 24, 2019

Commonwealth v. Ross: Is Bitemark Identification Evidence Becoming Toothless?

In a case that has received national attention, a Pennsylvania Superior Court (the state's intermediate appellate court) finally decided that the trial judge had to at least hold a hearing on the general scientific acceptance of bitemark identification evidence. The trial court had ruled that no such "Frye hearing" was required before admitting proposed testimony from two forensic odontologists that the defendant cannot be excluded as the source of human bite marks on the rape-murder victim whereas several other potential suspects can be.

Mysteriously, the appellate court chose to keep its lengthy opinion unreported and of "no precedential value." (It is reproduced at the end of this posting and available as a pdf file.) Many appellate courts do not publish opinions that simply apply settled law and would be of interest only to the parties, but that is not the situation here. The trial judge's refusal to grant the defense's request for such a "Frye hearing" has received national condemnation, 1/ and the new opinion is one of a very few to take seriously widespread misgivings about bitemark evidence.

As described in an NBC report complaining that "the justice system ignores science," 2/
A little after noon on June 24, 2004, a fisherman on Canoe Creek Lake in Blair County, Pennsylvania, found the bound, beaten and sexually abused body of Tina Miller near a boat launch. Suspicion focused on [Paul Aaron] Ross, who’d been with Miller nearby the night before.

There were no witnesses to the killing, leaving authorities to build a case on circumstantial evidence: a man who said he had dropped Miller and Ross off near the boat launch, former girlfriends who said he’d abused them, a mark found on one of Miller’s breasts, and items collected from the scene ─ including a shoe print and a beer bottle. None of it definitively linked Ross to the murder, and Ross denied killing Miller, asserting that another man had picked her up in a truck. But prosecutors argued that, taken collectively, the evidence proved his guilt.

He went to trial in 2005, and a bite-mark examiner helped seal his conviction.

The examiner, Dr. Dennis Asen, was a dentist with 25 years of experience identifying bodies by their teeth and examining bite marks. On the stand, he recalled viewing Miller’s body at the morgue and concluding that her breast bore patterns of a bite mark. He took a photograph of it and made an “overlay tracing” that he uploaded to a computer and compared with molds of Ross’ teeth and the teeth of four other suspects, including three who’d been in contact with Miller in the hours before her death. Asen said he found the mark “very highly consistent” only with Ross’ teeth. Asen acknowledged, however, that he couldn’t say with 100 percent certainty that Ross had made the mark. The defense hired its own bite-mark examiner, who said he was unable to determine whether Ross left the mark.

Ross was convicted of first-degree murder and sentenced to life in prison. But the conviction was overturned by an appeals court that ruled the trial court had “abused its discretion” in refusing to give Ross’ lawyer more time to prepare, and allowing the former girlfriends’ testimony.

Prosecutors plan to try Ross again, but the process has stalled amid a battle over the bite-mark evidence.

Defense lawyers, including members of the New York-based Innocence Project, have cited government reports and academic studies, including from the National Academy of Sciences, the President's Council of Advisors on Science and Technology and the Texas Forensic Science Commission.

The reports have shown that no one has sufficiently proven that human bite marks are unique, or that skin is a reliable material to record them ─ or that forensic dentists can reliably identify a human bite mark in the first place.
What was the Commonwealth's rejoinder? The Blair County district attorney is "The Honorable Richard A. Consiglio." (That is his title on the county's website, which emphasizes his success in dealth penalty cases along with his receipt of "an award ... for standing up to the Blair County Courts on behalf of the unborn." "Rich," as the website also refers to him, told now retired Blair County Judge Jolene Grubb Kopriva in 2016 that
the authors of scientific reports lack “real world” experience. He ... pointed out that no court in any state has ruled against admitting it. “This is evidence, your honor, that has been accepted for 40 or 50 years, not quite as old as I am, but 40 or 50 years, maybe longer, accepted by courts everywhere.” 3/
Acknowledging that "the use of bite-mark evidence is beginning to face challenges," Judge Kopriva ruled the evidence admissible on the basis of the lawyers' arguments. She wrote in Match 2017 that "it would be premature for this court to order that the methodology is no longer generally accepted in the relevant scientific community.” 4/

In a blog post (since deleted), "the Innocence Project described the case as an example of "'willful scientific illiteracy among the judiciary.' ... Judge Kopriva imposed a gag order preventing either side from talking publicly about the case outside of court." 5/

But she also certified an interlocutory appeal of her order denying the motion for a Frye hearing. (Ordinarily, such evidentiary rulings are only reviewed as part of an appeal from the verdict at the end of the trial.) The Superior Court refused to accept the interlocutory appeal. But then the Pennsylvania Supreme Court vacated the Superior Court's order and directed it to decide whether there had to be an evidentiary pretrial hearing on the admissibility of bitemark evidence

This week, on November 21, the Superior Court released its opinion. The court held that the trial court abused its discretion in agreeing to admit bitemark opinion testimony without first conducting a Frye hearing. The opinion, written by Judge Mary Murray, discusses Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), the Superior Court's understanding of the general-acceptance requirement as it has been construed in Pennsylvania, and how this requirement applies to a request for an evidentiary hearing on bitemark evidence.

According to the Ross opinion, "Frye contemplated a judicial inquiry, informed by experts, into the general acceptance of the scientific methods used." Yet, Frye contains no mention of "a judicial inquiry" in the form of a pretrial evidentiary hearing on the status of a method among scientists. Without any such hearing to draw on, the Court of Appeals in Frye determined that "the systolic blood pressure deception test has not yet gained such standing and scientific recognition among physiological and psychological authorities as would justify the courts in admitting expert testimony deduced from the discovery, development, and experiments thus far made." 6/ The court simply announced its conclusion in an enigmatic eight-paragraph opinion. The task of devising suitable substitutes for judicial fiat fell to later generations.

Today, the use of hearings with expert testimony on scientific acceptance is well developed. In Pennsylvania, however, the touchstone for deciding when such hearings are essential often is said to be "novelty." Thus, Judge Kopriva relied on the lack of novelty in denying the defense's requested hearing, and the Superior Court focuses on the supposed requirement as well.

But Frye itself imposed no "novelty" requirement. All that Frye said in this regard that was the blood pressure test had yet to cross "the line between the experimental and demonstrable stages." 7/ The opinion did not consider whether a procedure could cross the line, but then fall back once more into the darker side of "this twilight zone." 8/ Bitemark evidence once was thought to have been valid (by its practitioners at least), but, as the defense in Ross argued, today the larger scientific community (and a growing number of dental experts) do not recognize its scientific validity.

Fortunately, the Superior Court, after flailing about in an effort to decide what needed to be novel, also addressed the more appropriate question of whether the relevant scientific community still believes (if it ever did) that the kind of testimony that Judge Kopriva was going to admit is generally accepted. It rejected District Attorney Consiglio's idea that acceptance within the forensic odontology community is sufficient, and it recognized that recent literature indicated significant dissension even within that community and outright rejection by a broader scientific community. Consequently, it held that the trial court could not admit the prosecution's evidence without a meaningful hearing on general acceptance in the broader community.

Of course, this holding does not dictate the outcome of the hearing. Indeed, the trial court could avoid an evidentiary hearing entirely, by reviewing the readily available scientific literature (with briefing by the parties) and concluding that it does not support the general acceptance of the comparative analysis that the prosecution proposes to present. After all, the proponent of the scientific evidence bears the burden of demonstrating its general acceptance, and that will not easy for the state to do in this case.

Nonetheless, that is too great an about-face to expect from the trial court. More likely, the court will proceed with the full-blown hearing. That hearing should focus on the specific testimony that the two dentists slated to testify might give. Is there sufficient "scientific recognition" 9/ that the forensic odontologists can validly determine that the bite marks on the breast of the victim's partially submerged body are human (if that is what they propose to say)? That (whether or not the marks are from a human source) they do not come from the four other potential suspects? That they were "very highly consistent" with Ross's dentition (as Dr. Asen testified at the original trial)? If the testimony were kept to a bare minimum, such as "unable to exclude as a possible source of the marks," with no explanation of the implications of such an inclusion (because scientific knowledge is too thin), 10/ would it be sufficiently helpful to be admissible? 11/ Or would it be inadmissible as being inscrutable or too easily overvalued?

The time when these issues could be avoided by arguments about "novelty" and "real world experience" has passed.

  1. John Shuppe, 'We Are Going Backward': How the Justice System Ignores Science in the Pursuit of Convictions, NBS News, Jan. 23, 2019,
  2. Id.
  3. Id. There are exceptions to the District Attorney's bald assertion that "courts everywhere" deem bitemark testimony admissible. See infra note 11. Mr. Consiglio's timeline also was incorrect. The earliest use of bitemarks as identification in a U.S. criminal case may have been some 150 years ago, in 1870. See Barry E. Lipton et al., History of Odontology, in Manual of Forensic Odontology 1, 27 (David R. Senn & Richard A. Weems eds., 2013). The first reported case was a 1954 murder trial in Texas. Id. at 28. But see Michael J. Saks et al., Forensic Bitemark Identification: Weak Foundations, Exaggerated Claims, 3 J. L. & Biosci. 538 (2016), available at (asserting that before 1974 a some years thereafter, it was "the rule among forensic dentists that crime scene bite marks could not be trusted to yield accurate source identifications.).
  4. Id.
  5. Id.
  6. Frye v. United States, 293 F. 1013, 1014 ( D.C.. Cir 1923).
  7. Id.
  8. Id. 
  9. Id.
  10. This seems to be the only type of inclusionary testimony the American Board of Forensic Odontology accepts from its members. See ABFO, Standards and Guidelines for Evaluating Bitemarks § 3 (2018) ("bitemark linkage conclusions should  only a) exclude  or b) not exclude  (include) a  dentition.The  specific  terms  found  in 2.c.are: a)  for  exclusion, Excluded  as Having  Made  the  Bitemark,  and  b)  for  inclusion, Not  Excluded  as  Having Made  the  Bitemark.Stronger  terms of  attribution are  not condoned ... .").
  11. Cf. Ege v. Yukins, 485 F.3d 364 (6th Cir. 2007) (the more useful testimony of exclusions and "highly consistent" matching followed by "my expert opinion" that "nobody else" among the "three and a half million people" in the Detroit area "would match up" was without foundation and violated due process). The American Board of Forensic Odontology no longer condones such testimony. See supra note 10..

Commonwealth v. Ross
No. 1738 WDA 2018 (Pa. Super. Ct. Nov. 21, 2019)
(not reported, pdf file available at


Paul Aaron Ross (Appellant) appeals from the order denying his request for a Frye hearing. 1/ After careful consideration, we vacate the trial court’s order denying Appellant’s request for a Frye hearing and remand to the trial court for proceedings consistent with this decision.

This appeal arises from the June 27, 2004 murder of Tina Miller at Canoe Creek Lake in Canoe Creek State Park. Appellant was arrested and charged with Ms. Miller’s murder. On November 23, 2005, a jury found Appellant guilty of first-degree murder, aggravated assault, involuntary deviate sexual intercourse, unlawful restraint, simple assault, false imprisonment, and indecent assault. 2/
A prior panel of this Court summarized the post-trial procedural history:
At the sentencing phase of the trial, the jury rejected imposition of the death penalty. The trial court then proceeded to sentence [Appellant] to life in prison plus 24 to 48 years. [Appellant] filed post-trial motions, which the trial court denied on January 30, 2006. On February 10, 2006, [Appellant] filed a timely notice of appeal, but [Appellant’s] counsel failed to file an appellate brief and the appeal was consequently dismissed. On September 26, 2008, [Appellant] filed a PCRA petition seeking the reinstatement nunc pro tunc of his direct appeal rights, which the trial court granted on August 14, 2009.
Commonwealth v. Ross, 57 A.3d 85, 90 (Pa. Super. 2012) (en banc).

On October 12, 2012, an en banc panel of this Court vacated Appellant’s judgment of sentence and remanded for a new trial. Id. at 105. On November 17, 2015, the Pennsylvania Supreme Court denied the Commonwealth’s petition for allowance of appeal.

On March 1, 2016, Appellant filed pre-trial motions in which he sought, inter alia, the exclusion of any expert evidence relating to bite mark identification and a Frye hearing. At trial, the Commonwealth intends to introduce the testimony of Dr. Dennis Asen (Dr. Asen) and Dr. Lawrence Dobrin (Dr. Dobrin). Dr. Asen and Dr. Dobrin are both dentists and practice in the field of forensic odontology (the study of the structure of teeth). Dr. Asen and Dr. Dobrin intend to testify that the mark on Ms. Miller’s left breast was caused by a human bite, and when they compared five sets of teeth molds, including one from Appellant, Dr. Asen and Dr. Dobrin could exclude four of the molds from having made the bite mark, but not Appellant’s.

On December 2, 2016, following the filing of several supplemental motions by Appellant and objections by the Commonwealth, the trial court heard oral argument on Appellant’s request for a Frye hearing. On March 8, 2017, after the parties submitted additional briefs on Appellant’s request for a Frye hearing, the trial court entered an order concluding that bite mark identification evidence is not novel and therefore a Frye hearing was not warranted. The court further provided that the Commonwealth’s experts were to adhere to the guidelines set forth by the American Board of Forensic Odontologists (ABFO).

On April 5, 2017, Appellant filed a motion to amend the March 8, 2017 order to include language relating to Pennsylvania Rule of Evidence 702(c), so that the trial court could address whether the expert methodology is generally accepted in the relevant field. Appellant also requested that the court certify for immediate appeal its decision not to hold a Frye hearing on the bite mark identification evidence.

On November 6, 2017, the trial court entered an amended order once again denying Appellant’s request for a Frye hearing. The trial court also included in the order language addressing Rule 702(c) and granting Appellant’s request for certification of immediate appeal. On December 5, 2017, Appellant filed a petition for permission to file an interlocutory appeal with this Court, which we denied by per curiam order on May 7, 2018. On June 1, 2018, Appellant filed a petition for allowance of appeal to the Pennsylvania Supreme Court. On November 20, 2018, our Supreme Court granted Appellant’s petition for allowance of appeal, vacated this Court’s order denying Appellant’s petition for permission to file an interlocutory appeal, and remanded the case to this Court for disposition.

On appeal, Appellant presents the following issues for review:
Appellant’s Brief at 5.

Both of Appellant’s issues related. Therefore, we address them together. We begin with our standard of review:
As a general rule, this Court’s standard of review of a trial court’s evidentiary ruling, including a ruling whether expert scientific evidence is admissible against a Frye challenge, is limited to determining whether the trial court abused its discretion. Grady v. Frito–Lay, Inc., 839 A.2d 1038, 1046 (Pa. 2003); Zieber v. Bogert, 773 A.2d 758, 760 n.3 (Pa. 2001) (citing Commonwealth v. Minerd, 753 A.2d 225 (Pa. 2000)). “An abuse of discretion may not be found merely because an appellate court might have reached a different conclusion, but requires a result of manifest unreasonableness, or partiality, prejudice, bias, or ill-will, or such lack of support so as to be clearly erroneous.” Grady, 839 A.2d at 1046 (citing Paden v. Baker Concrete Constr., Inc., 658 A.2d 341, 343 (Pa. 1995)).
Commonwealth v. Dengler, 890 A.2d 372, 379 (Pa. 2005) (citations modified).

Appellant argues that the trial court abused its discretion in denying his request for a Frye hearing on the admissibility of the Commonwealth’s bite mark identification evidence. This Court recently articulated the legal standards implicated by a Frye analysis:
The Frye standard originally was intended to prevent the situation in which a party would seek to introduce scientific evidence that was so new that it would be impossible to “produce rebuttal experts, equally conversant with the mechanics and methods of a particular technique.” [U.S.] v. Addison, 498 F.2d 741, 744 (D.C. App. 1974). Frye contemplated a judicial inquiry, informed by experts, into the general acceptance of the scientific methods used. The standard required that “the thing from which the [expert’s] deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.” Frye, supra at 1014. At issue in Frye was admissibility of the systolic blood pressure deception test, commonly known as the lie detector test. The trial court excluded the evidence, and the court affirmed that ruling on appeal, explaining:
Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.
Frye, supra at 1014. Pennsylvania adopted the Frye standard in Commonwealth v. Topa, 369 A.2d 1277 (Pa. 1977), a case involving the propriety of the trial court’s admission of voice print identification evidence through an expert, Lieutenant Nash, of the Michigan State Police. Our High Court, applying Frye, reasoned that
[t]he requirement of general acceptance in the scientific community assures that those most qualified to assess the general validity of a scientific method will have the determinative voice. Additionally, the Frye test protects prosecution and defense alike by assuring that a minimal reserve of experts exists who can critically examine the validity of a scientific determination in a particular case. Since scientific proof may in some instances assume a posture of mystic infallibility in the eyes of a jury of laymen, the ability to produce rebuttal experts, equally conversant with the mechanics and methods of a particular technique, may prove to be essential.
Topa, supra at 1282 (quoting Addison, supra at 744). The Topa Court went on to conclude that the testimony of one expert could not satisfy this standard, citing commentaries questioning the reliability of sound spectrographs and voiceprints and demonstrating that it was not generally accepted within the field of acoustical science.
Thus, the Frye standard originally was intended to prevent a party from introducing scientific evidence that was so new that it would be impossible to “produce rebuttal experts, equally conversant with the mechanics and methods of a particular technique.” Addison, supra at 744. Frye contemplated a judicial inquiry, informed by experts, into the general acceptance of the scientific methods used.

In the years since the adoption of the Frye standard, this Court has clarified that “Frye only applies to determine if the relevant scientific community has generally accepted the principles and methodology the scientist employs, not the conclusions the scientist reaches.” Trach v. Fellin, 817 A.2d 1102, 1112 (Pa.Super. 2003) (en banc).
Walsh v. BASF Corp., 191 A.3d 838, 842-43 (Pa. Super. 2018), appeal granted, 203 A.3d 976 (Pa. 2019). 3/

The above principles have been incorporated into Pennsylvania Rule of Evidence 702, which states:
A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if: (a) The expert’s scientific, technical, or other specialized knowledge is beyond that possessed by the average layperson; (b) The expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (c) The expert’s methodology is generally accepted in the relevant field. Pa.R.E. 702 (emphasis added).
Appellant argues that the trial court erred in determining a Frye hearing was unnecessary in this case. Appellant asserts that the court wrongly concluded that the methodology employed by the Commonwealth’s experts in conducting their bite mark identification analysis was generally accepted in the scientific community of forensic odontology. Additionally, Appellant contends that the trial court should have examined whether the expert’s methodology for bite mark identification analysis was generally accepted in the broader scientific community, as opposed to limiting its examination to the field of forensic odontology. Appellant maintains that bite mark identification analysis has applications in several different scientific communities, and several of these communities have determined that bite mark identification analysis is not reliable and has little or no evidentiary value.

In support of his argument, Appellant relies on our Supreme Court’s decision in Betz v. Pneumo Abex, LLC, 44 A.3d 27 (Pa. 2012). At issue in Betz was the admissibility of expert opinion evidence relating to the “any-exposure” theory of legal causation, i.e., “that each and every exposure to asbestos – no matter how small – contributes substantially to the development of asbestos-related diseases.” Id. at 30. As part of its analysis, the Supreme Court had to first address, as a threshold issue, whether the trial court was correct in concluding that a Frye hearing was necessary to determine the admissibility of the “any-exposure” evidence. Id. at 52-55.

In concluding that the trial court’s decision to conduct a Frye hearing was correct, the Supreme Court explained:
There is inherent tension among the various measures for admissibility of expert testimony. The threshold common law test requires merely some reasonable pretension to specialized knowledge. See, e.g., Miller v. Brass Rail Tavern, Inc., 664 A.2d 525, 528 (Pa. 1995). Our evidentiary rules, on the other hand, suggest trial courts may take a greater role in assessing whether the testimony will assist the trier of fact to understand the evidence or determine a fact in issue, see Pa.R.E. 702, and in screening evidence to avoid unfair prejudice, confusion of the issues, or misleading of the jury, see Pa.R.E. 403. For better or for worse, however, in the context of the more conventional realms of science, the Pennsylvania decisions tend to downplay the courts’ screening function. See, e.g., Commonwealth v. Nazarovitch, 436 A.2d 170, 172 (Pa. 1981) (“[C]ourts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery[.]” (quoting Frye, 293 F. at 1014)). A manifestation of this trend is that challenges generally are vetted through the Frye litmus, which winnows the field of the attacks by application of the threshold requirement of novelty. See Grady, 839 A.2d at 1043-44.

Various reasons underlie the preference to limit the courts’ involvement in determining the admissibility of scientific evidence. There is the concern that liberality in allowing challenges would substantially increase the number of challenges (and cases in which lengthy pre-trial proceedings would ensue). The competency of trial judges to accept or reject scientific theories remains a legitimate subject of controversy. Additionally, a claim or defense in many cases may rise or fall based upon expert testimony and, therefore, there is some reluctance on the part of courts to deprive litigants of their day in court.

On the other hand, this Court has recognized the influential nature of expert testimony on complex subjects, and the potential that distortions have to mislead laypersons. See id. at 1045; Topa, 369 A.2d at 1281-82. It would be naïve, in this regard, to assume that the possibility for distortion is limited to the very newest realms of science. Cf. Grady, 839 A.2d at 1045 (explaining that Frye applies not only to novel science, but also where scientific methods are utilized in a novel way).

We therefore agree with Appellants that a reasonably broad meaning should be ascribed to the term “novel.” Furthermore, we conclude that a Frye hearing is warranted when a trial judge has articulable grounds to believe that an expert witness has not applied accepted scientific methodology in a conventional fashion in reaching his or her conclusions. Accord id. We believe a narrower approach would unduly constrain trial courts in the appropriate exercise of their discretion in determining the admissibility of evidence. See id. at 1046.
Id. at 52-53 (emphasis added, footnote omitted, citations modified).

Additionally, in Betz, the Supreme Court rejected the notion that the defendants could not challenge the methodology of the plaintiff’s expert pathologist with the testimony of risk assessors, toxicologists, and epidemiologists. Id. at 54. The Court reasoned that the expert pathologist’s “any-exposure” opinion “was not couched in terms of a methodology or standard peculiar to the field of pathology[,]” and “was plainly grounded on risk assessment.” Id. at 54-55. Thus, the Supreme Court determined that the subjects at issue “are not within the particular expertise of a pathologist, but, rather, are interdisciplinary in character.” Id. at 55.

In this case, the trial court reached two conclusions in denying Appellant’s request for a Frye hearing. First, the trial court determined that “[b]ite mark evidence is currently generally accepted in the relevant scientific community of forensic odontologists.” Trial Court Opinion, 11/6/17, at 5. The court explained:
The American Board of Forensic Odonotologists (ABFO) has promulgated guidelines regarding the approved methodology concerning bite mark evidence. This [c]ourt notes that the aforementioned methodology rejects the notion that human dentitions are unique to the individual. Any evidence proffered by the Commonwealth to suggest that an individual can be identified by a bite mark, rather than merely excluded or not excluded as having made the mark, would be inadmissible.

Second, the trial court rejected Appellant’s reliance on Betz, finding that case distinguishable:
It is true that the Pennsylvania Supreme Court allowed the Betz defendants to address the methodology of a pathologist through the testimony of risk assessors, toxicologists, and epidemiologists. However, Betz can be distinguished from the instant case. The Betz Court found that the pathologist’s opinion was not “couched in terms of a methodology or standard peculiar to the field of pathology.” [Betz, 44 A.3d at 54]. Rather, the pathologist’s opinion was “plainly grounded on risk assessment” and was “interdisciplinary in character.” Id. at 55. The Betz Court based its decision not upon the role of pathologists generally, but upon the specific methodology employed by the individual pathologist in question. Betz does not make a broad assertion that Pennsylvania law “mandates a broader definition of the relevant scientific community” where the methodology of a pathologist is at issue. Here, the Commonwealth does not seek to offer the kind of broad-scale scientific testimony that was at issue in Betz.
Id. at 6.

After careful consideration, we find support for Appellant’s position that a Frye hearing was warranted in this case. First, with respect to the trial court’s conclusion that bite mark identification analysis has general acceptance in the field of forensic odontology, Appellant offered evidence indicating that there is a lack of consensus among forensic odontologists on whether bite mark identification analysis is reliable and valid. While there is no dispute that the ABFO has established standards and a methodology for conducting bite mark identification analysis, see Commonwealth’s Third Brief in Opposition to Appellant’s Request for a Frye Hearing, 2/21/17, Exhibit B, Appellant presented numerous reports to the trial court indicating that practitioners within the community of forensic odontology question whether this methodology reliably enables forensic odontologists to identify an injury as a human bite mark.

For example, Appellant presented evidence from a presentation by Dr. David Senn, DDS, Vice-President of the American Board of Forensic Odontology, to the National Academies: Committee on Identifying the Needs of the Scientific Community. See Defendant’s Post-Argument Supplement to “Defendant’s Motion in Limine: Frye Test – Bite Mark Evidence” (hereinafter Defendant’s Post-Argument Supplement), 1/17/17, Exhibit 4 (Presentation to the National Academies: Committee on Identifying the Needs of the Forensic Science Community – Forensic Odontology Bite Marks (hereinafter Senn Presentation), 4/23/07, at 31-34). While Dr. Senn opined that bite mark identification analysis was important to the investigation and adjudication of certain crimes, id. at 45, Dr. Senn identified several “major problems” with bite mark identification analyses, including: “[t]he uniqueness of the human dentition has not been scientifically established”; “[t]he ability of the dentition, if unique, to transfer a unique pattern to human skin and maintain that uniqueness has not been scientifically established”; “[a] clear statement of the type, quality, and number of class and individual characteristics or other features required to indicate that a bite mark has reached a threshold of evidentiary value has not been established”; and “Forensic Odontology certifying organizations have not created or administered bite mark analysis proficiency tests for their board certified members.” Id. at 31-34.

Likewise, Appellant presented a report by the President’s Council of Advisors on Science and Technology, which revealed the following:
Empirical research suggest that forensic odontologists do not consistently agree even on whether an injury is a human bitemark at all. A study of the American Board of Forensic Odontology (ABFO) involved showing photos of 100 patterned injuries to ABFO board-certified bitemark analysts, and asking them to answer three basic questions concerning (1) whether there was sufficient evidence to render an opinion as to whether the patterned injury is a human bitemark; (2) whether the mark is a human bitemark, suggestive of a human bitemark, or not a human bitemark; and (3) whether distinct features (arches and toothmarks) were identifiable. Among the 38 examiners who completed the study, it was reported that there was unanimous agreement on the first question in only 4 of the 100 cases and agreement of at least 90 percent in only 20 of the 100 cases. Across all three questions, there was agreement of at least 90 percent in only 8 of the 100 cases.

The studies proffered by Appellant challenge the trial court’s conclusion that the ABFO’s methodology for using bite marks to eliminate persons as suspects is generally accepted in the field of forensic odontology. These reports reflect that individuals within the forensic odontology community question not only whether the ABFO’s methodology can reliably aid experts in using bite marks to validly identify or exclude individuals as criminal actors, but also whether the methodology enables experts to identify a wound as a human bite mark. Therefore, Appellant provided the trial court with articulable grounds that the Commonwealth’s expert witnesses on bite mark identification analysis have not applied accepted scientific methodology in reaching their conclusions. See Betz, 44 A.3d at 53. Accordingly, we conclude that the trial court abused its discretion in denying Appellant’s request for a Frye hearing.

We are likewise persuaded by Appellant’s argument that the trial court should not have limited consideration of the general acceptance of the experts’ methodology in this case to the field of forensic odontology. As several of the reports Appellant cites reflect, bite mark identification analysis implicates numerous scientific fields. See generally Defendant’s Post-Argument Supplement, 1/17/17, Exhibit 2 (NATIONAL ACADEMY OF SCIENCES, COMMITTEE ON IDENTIFYING THE NEEDS OF THE FORENSIC SCIENCES COMMUNITY, STRENGTHENING FORENSIC SCIENCE IN THE UNITED STATES: A PATH FORWARD (2009), Exhibit 5 (PCAST Report), Exhibit 11 (Michael J. Saks, et al., Forensic bitemark identification: weak foundations, exaggerated claims, 3(3) J. LAW BIOSCI. 1 (2016)). As these studies indicate, bite mark identification analysis not only involves concepts relating to forensic science generally, but also pathology, biology, statistics, and metrology. See Defendant’s Post-Argument Supplement, 1/17/17, Exhibit 11 (Michael J. Saks, et al., Forensic bitemark identification: weak foundations, exaggerated claims, 3(3) J. LAW BIOSCI. 1 (2016)) (noting that the forensic identification process is “fundamentally probabilistic” and that it involves the interplay of different scientific disciplines including blood (pathology), skin (biology and dermatology), and measurements (metrology)). Because the act of biting a human involves not only the biter’s teeth, but also the skin, muscle, tissue, and blood with which the teeth make contact, the notion that bite mark identification analysis involves scientific disciplines beyond forensic odontology is reasonable.

Finally, we emphasize that our decision in no way represents a determination as to the general acceptance of the methodology underlying bite mark identification analysis utilized by the Commonwealth’s experts in this case. We make no judgment as to the admissibility of the bite mark identification evidence at issue. Rather, we simply conclude that Appellant provided the trial court with articulable grounds to believe that the Commonwealth’s expert witnesses on bite mark identification analysis may not have applied generally accepted scientific methodology in reaching their conclusions, and consequently, the trial court erred in concluding that a Frye hearing was not necessary. While Appellant’s evidence expresses negative opinions on bite mark identification analysis, we cite it only to support our conclusion that a Frye hearing is proper for the resolution of these discrepancies, and to afford both parties the opportunity to present evidence in support of their positions. Therefore, we vacate the order denying Appellant’s request for a Frye hearing and remand this matter to the trial court for a hearing in accordance with Frye.

Order vacated. Case remanded. Jurisdiction relinquished. Judgment Entered.


* Retired Senior Judge assigned to the Superior Court.
1. A Frye hearing, named after the decision in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), “is a hearing held for the trial court to determine whether the general scientific community has reached a general acceptance of the principles and methodology used by the expert witness.” Commonwealth v. Walker, 92 A.3d 766, 769 n.1 (Pa. 2014).
2. 18 Pa.C.S.A. §§ 2501(a), 2702(a)(1), 3123(a)(1), 2902(a)(1), 2701(a)(1), 2903(a), 3126(a)(2).
3. This case was argued before our Supreme Court on October 15, 2019, and is awaiting disposition. See Walsh v. BASF Corp., 203 A.3d 976 (Pa. 2019). The issue before our Supreme Court is whether, in conducting a Frye analysis, “trial courts are not permitted to act as ‘gatekeepers’ to ensure the relevance and reliability of scientific studies offered by experts to support their opinions by scrutinizing whether those studies actually support their opinions.” Id. at 978. While the Supreme Court may overturn our Walsh decision, their disposition will have no bearing on the outcome of this case or the general standards triggering the necessity of a Frye hearing that were thoughtfully set forth in the Walsh decision.