May No Longer Testify That Fingerprints 'Match'
Shannon P. Duffy
The Legal Intelligencer
January 9, 2002
For the first time, a federal judge has ruled that fingerprint experts cannot tell juries that two fingerprints are a "match" because the science they rely on does not meet the U.S. Supreme Court's Daubert test.
But Senior U.S. District Judge Louis H. Pollak of the Eastern District of Pennsylvania stopped short of tossing out all fingerprint testimony in United States v. Plaza, saying such a ruling would be "unwarrantably heavy-handed."
Instead, Pollak sided with the government by taking "judicial notice" of the fact that fingerprints are both "unique" and "permanent."
He then ruled that the experts on both sides can testify about how the prints were obtained and the similarities and differences between them, but are barred from expressing any opinion about whether the prints are a "match."
The ruling is a huge victory for the criminal defense bar, especially since it comes from a judge with the stature of Pollak, a former dean of both the Yale and University of Pennsylvania law schools who is routinely invited to sit on the U.S. Court of Appeals.
"This is a ground-breaking, extremely important opinion," said Assistant Federal Defender Robert Epstein.
But Epstein said the decision should come as no surprise to those who have been following the issue because "it has long been predicted by the forensic science community."
Epstein has no connection to the Plaza case, but nonetheless played a significant role by supplying the defense lawyers with the briefs he submitted in a previous case.
Judge Pollak incorporated the entire record from Epstein's case, United States v. Mitchell, in which Judge J. Curtis Joyner held five days of hearings before denying the defense request from the bench.
The Plaza defense team -- L. Felipe Restrepo of Philadelphia's Krasner & Restrepo; Jules Epstein of Kairys Rudovsky Epstein & Messing in Philadelphia; Gerald Stein; Bernard Siegel and Michael Giampetro -- argued that fingerprint evidence has never been properly subjected to the rigors of a Daubert test and that, when it is, it fails.
"Numerous forensic science commentators have now come to recognize that the field is scientifically bankrupt," they wrote.
Judge Pollak found that the issue boiled down to two questions:
1) Whether each individual has a unique set of fingerprints and, if so, whether these unique fingerprints are permanent.
2) Whether latent prints -- fragments of fingerprints "lifted" from a surface touched by an unidentified person -- can accurately be matched to "rolled" prints -- complete fingerprints that are obtained from an identified person through established fingerprinting procedures.
In the first section of the 49-page opinion, Pollak reviewed the science of fingerprints, relying heavily on the testimony of a government witness, Dr. William Babler, a former President of the American Dermatoglyphics Association who works as a professor of gross anatomy and embryologist.
Babler testified that fingerprints start forming when a fetus is in the ninth or 10th week of development and are permanently fixed by about the 17th week.
Pollak also found that fingerprint examiners refer to three levels of detail that can be observed on mature fingerprints. At the first level of detail, an examiner looks at the overall pattern of a fingerprint -- whorl patterns, loop patterns, and arch patterns.
In some states and in some foreign jurisdictions, fingerprint examiners must find a minimum number of so-called "Galton points," or characteristics on the fingerprint ridges, in common before they can declare a match with absolute certainty. But the FBI switched from relying on a mandatory minimum number of points to no minimum number in the late 1940s.
Since Daubert, Pollak said, several federal judges have addressed the issue of whether fingerprint identifications are admissible as expert testimony under Federal Rule of Evidence 702 -- including two Eastern District of Pennsylvania judges -- and all have come to the conclusion that fingerprint testimony should be admitted.
But Pollak found that the science of fingerprint identification as it currently exists fails the Daubert test for several reasons.
Pollak focused on the process fingerprint examiners employ which is known as "ridgeology" or ACE-V, an acronym for "analysis," "comparison," "evaluation" and "verification."
Prosecutors argued that "the ACE-V process and the experts' conclusions have been tested empirically over a period of 100 years."
But Pollak found that fingerprint science hasn't truly been "tested" in the scientific sense just because they have been disputed in trials.
"Adversarial testing in court is not what the Supreme Court meant when it discussed testing as an admissibility factor," Pollak wrote.
"It makes sense to rely on scientific testing, rather than 'adversarial' courtroom testing, because to rely on the latter would be to vitiate the gatekeeping role of federal trial judges. ... If 'adversarial' testing were the benchmark -- that is if the validity of a technique were submitted to the jury in each instance -- then the preliminary role of the judge in determining the scientific validity of a technique would never come into play," he wrote.
"Thus, even 100 years of 'adversarial' testing in court cannot substitute for scientific testing when the proposed expert testimony is presented as scientific in nature."
Pollak found that the government "had little success in identifying scientific testing that tended to establish the reliability of fingerprint identifications."
By contrast, he said, the defense lawyers presented testimony that "strongly suggested that fingerprint identification techniques have not been tested in a manner that could be properly characterized as scientific."
Pollak said he was particularly impressed by the testimony of forensic scientist David Stoney, the director of the McCrone Research Institute in Chicago, who said: "The determination that a fingerprint examiner makes ... when comparing a latent fingerprint with a known fingerprint, specifically the determination that there is sufficient basis for an absolute identification, is not a scientific determination. It is a subjective determination standard. It is a subjective determination without objective standards to it."
Government experts also confirmed Stoney's testimony that fingerprint identification is "a subjective determination," Pollak noted.
Turning to the second Daubert factor -- whether the theory or technique has been subjected to peer review and publication -- Pollak again sided with the defense.
Prosecutors argued that "the fingerprint field and its theories and techniques have been published and peer reviewed during a period of over 100 years."
But Pollak found that the writings to date don't satisfy Daubert.
"It is the case that there are numerous writings that discuss the fingerprint identification techniques employed by fingerprint examiners. But it is not apparent that their publication constitutes 'submission to the scrutiny of the scientific community' in the Daubert sense."
Even those at the top of the fingerprint identification field, he said, "tend to be skilled professionals who have learned their craft on the job and without any concomitant advanced academic training."
As a result, Pollak concluded that "it would thus be a misnomer to call fingerprint examiners a 'scientific community' in the Daubert sense."
The third Daubert factor -- that trial judges consider the known or potential rate of error and the existence and maintenance of standards controlling the technique's operation -- also weighed in the defense's favor, Pollak found.
Error rates have never been thoroughly studied, Pollak found, but the U.S. Department of Justice has recently recognized the need for such a study by authorizing funding for it.
Pollak found that the varying standards used by different states in the United States and by other countries shows that the science does not depend on a uniform standard.
While witnesses said the ACE-V process is the method in general use among fingerprint examiners in the United States, Pollak found that "the application of this method, in particular whether a minimum number of Galton points must be identified before a match can be declared, varies from jurisdiction to jurisdiction."
The United Kingdom employs a 16-point minimum, Australia mandates that 12 points be found in common and Canada uses no minimum point standard.
In the United States, state jurisdictions set their own minimum point standards, while the FBI has no minimum number that must be identified to declare an "absolutely him" match, but does rely on a 12-point "quality assurance" standard, Pollak noted.
Pollak concluded that "while there may be good reason for not relying on a minimum point standard -- or for requiring a minimum number, as some state and foreign jurisdictions do -- it is evident that there is no one standard controlling the technique's operation."