Judge reverses limits on fingerprint testimony

A federal judge who stunned the legal community earlier this year by forbidding use of a fingerprint expert's opinion in a Philadelphia murder trial, reversed his decision Wednesday.

Noting that a three-day hearing two weeks ago provided new information, U.S. District Judge Louis Pollak said, "I have changed my mind."

The 59-page ruling is a major setback for lawyers across the United States who have been raising a series of legal challenges to fingerprint evidence. The challenges began emerging because of U.S. Supreme Court rulings in recent years that have imposed more rigorous standards for the admission of scientific and expert testimony.

Until Pollak's initial ruling in their favor on Jan. 7, the challengers had suffered one defeat after another. They considered the ruling a turning point that would become the basis for successful challenges in other courtrooms.

"It definitely throws a wet blanket on their hopes," said David Faigman, a law professor at the Hastings School of Law in San Francisco.

U.S. Attorney Patrick Meehan, whose office is prosecuting the Philadelphia murder trial in which fingerprints are key evidence, called the decision a major victory.

"It is certainly an important conclusion for law enforcement," he said.

In his earlier ruling, Pollak said that fingerprint comparison techniques have not been adequately validated through research studies, that they don't incorporate means of determining how often examiners err and that they don't use objective standards for determining whether two prints match. As a result, he said in January, an expert would be allowed to identify matching details of prints but could not specifically say that a defendant's print matched those found at the scene.

In his ruling Wednesday, Pollak reversed one of his major findings: that the subjectivity of fingerprint comparisons meant that the techniques for matching crime scene prints with known prints was not governed by any describable set of standards.

"On further reflection, I disagree with myself," wrote Pollak, a former dean of Yale Law School.

While continuing to maintain that fingerprint examiners' opinions are subjective, Pollak concluded Wednesday that they are no more subjective than many other forensic science opinions accepted in court. Moreover, he said fingerprint techniques allow for less subjectivity than many other fields of expertise.

Pollak held to his earlier opinion that the reliability of fingerprint methods have not been subjected to scientific testing and said such tests "would clearly aid in measuring (the techniques') reliability."

But he said defense lawyers in the case have not shown that the FBI, which did the fingerprint analysis, has a high error rate.

"With those findings in mind, I am not persuaded that the courts should defer admission of testimony on fingerprinting ... until academic investigators ... have made substantial headway on a verification and validation research agenda."

Although Pollak accepted the reliability of the FBI's examiners in this case, he was clearly unimpressed with the agency's proficiency tests it gives to its examiners to test their error rates.

He accepted the defense arguments that the tests were too simple and did not adequately test real fingerprint comparisons.

"On the record before me, the FBI examiners got very high proficiency grades, but the tests they took did not," he said.

Pollak also held firm to his January opinion that fingerprinting is not a science, a claim that experts in the field continue to maintain. But he said the Supreme Court rulings do not require that expert testimony be scientific testimony.