As the Whorl Turns

Long the Difference Between Guilt and Innocence, Fingerprints Themselves Are on Trial

The case against Robert Hood is far from airtight. The Colorado Springs resident is charged with aggravated robbery and kidnapping; in June, he allegedly forced his victim into a car trunk at gunpoint and drove him around for hours, demanding his ATM password, before abandoning the vehicle at a 7-Eleven. When the victim mentioned that his attacker sported a gold tooth, detectives immediately keyed on Hood, who is also a suspect in a separate murder case.

Besides that lustrous tooth, however, Hood seems like the wrong guy—at least according to his lawyer. The victim said his kidnapper stood 5 feet 11; Hood is barely 5-4. The victim described the attacker's hair as short, dark, and curly; Hood has been bald for years. The victim stated that his tormentor spoke with no discernible accent; Hood speaks with a thick Memphis drawl. According to public defender Deborah Grohs, the victim even fingered someone else. "The day after the man was robbed, he was on the street and he saw the man who robbed him," she says. "The police didn't follow up on it. We found that dude, and he's got a gold tooth! But they arrested Robert anyway."

The weak identification didn't bother the cops one bit. They lifted several partial fingerprints from the vehicle, and a faint palm impression was linked to Hood. That's usually enough to force a plea bargain, since fingerprints have been considered rock-solid forensic evidence for nearly a century.

illustration: Jack Black

But a growing number of legal experts are now questioning whether fingerprints deserve to be a legal slam dunk; they believe that matching crime-scene prints to suspects is more an art than a science, and an imprecise one at that. The skeptics were heartened on January 7, when a court in Philadelphia ruled that fingerprints should not be characterized as scientific evidence. That decision, in the murder-for-hire case U.S. v. Plaza, roiled a forensic discipline once considered beyond reproach, and prosecutors begged Judge Louis Pollak to reconsider. Last week, to the surprise of many, Pollak stepped back from the brink—though he maintains that the science is unproven, he will allow fingerprint experts to offer opinions in his courtroom.

Still, the willingness of so prominent a jurist to seriously question the validity of fingerprints should encourage a fresh wave of challenges. "This is one decision by one trial judge," says Robert Epstein, the public defender in Plaza. "Ultimately, the court of appeals is going to resolve this issue, either in this case or in some other case."

Unfortunately for those who claim to have been wrongfully convicted on the basis of shoddy fingerprints, the present furor won't be a ticket to freedom. Unlike revelations provided by DNA evidence, which can positively verify a convict's innocence, a post-verdict quibble over fingerprints will carry little legal heft. But the uproar has given hope to current defendants like Hood, who formerly stood almost no chance of beating a rap once a fingerprint examiner took the stand. "I've been doing this for 17 years, and every fingerprint case we ever got before, you'd go, 'Fingerprint case? Oh, better plead,' " says Grohs. "We never attacked the reliability of the procedure."

The fingerprint brouhaha has its roots in a 1993 Supreme Court decision, Daubert v. Merrell Dow Pharmaceuticals. For 70 years, scientific testimony had been governed by the so-called Frye standard, which required only that scientific evidence enjoy "general acceptance" to be admissible. Daubert raised the bar significantly, mandating that scientific techniques undergo rigorous testing and peer review. Justice Harry Blackmun, author of the court's opinion, also wrote that a technique should have a "known or potential rate of error . . . and the existence and maintenance of standards controlling the technique's operation."

Given the strictness of those criteria, some legal observers wondered whether fingerprints could pass muster. Despite the widespread acceptance of fingerprints among courts and the public alike—how many Law & Order plots could work without them?—the technique has seldom endured laboratory scrutiny. The methods by which examiners analyze loops and whorls date back to the late 19th century, when phrenology and water cures were the rage, and have changed little since. Simon Cole, author of Suspect Identities: A History of Fingerprinting and Criminal Identification, says that untrained records clerks, not doctors, pioneered the use of fingerprinting for law enforcement purposes; they wantonly added the authoritative-sounding letters FPE to their names, though historians argue over whether the E stood for examiner or expert.

"Just because these guys don't have college degrees or Ph.D.'s, it doesn't mean they don't know what they're talking about," says Cole, who himself holds a Ph.D. in science and technology studies from Cornell. "It could be that it's just an experience-based skill that they've acquired, like an artisanal skill. . . . It's just that you shouldn't call it science."

By the late 1920s, few if any courts doubted that fingerprints qualified as ironclad scientific evidence. In 1930, for example, an Oklahoma court cited a scene in Mark Twain's Pudd'nhead Wilson as proof that fingerprints were a valid tool for criminal identification. Cole maintains that dissent was squelched by an unspoken professional code he calls "the occupational norm of unanimity—the creation of this sense that fingerprint [examination] should not be a profession of dueling experts on the stand. . . . If you made an identification, then the whole rest of the profession should back you up."

When Daubert entered the books, several law professors balked at the dearth of formal studies and lack of an error scale. They were especially troubled by the use of "latent" fingerprints, which are recovered with the aid of chemicals or ultraviolet light. Latent prints are typically faint or incomplete, and thus tricky to match to an immaculate "rolled" print taken in a police station. In a series of tests conducted by a company called Collaborative Testing Service from 1995 to 2001, misidentification rates for latent prints ranged from 3 to 20 percent.

Prominent legal minds called for fingerprints to be subject to the same scientific inquiry as DNA, the validity of which has been proven time and again in laboratory studies. "A vote to admit fingerprints [as evidence] is a rejection of conventional science as the criterion for admission," wrote Michael Saks, an Arizona State University law professor, in 1998. "A vote for science is a vote to exclude fingerprint expert opinions."

Inspired by such rhetoric, defense lawyers launched a slew of fingerprint challenges, beginning in 1999. All were curtly rejected. "The reaction I got was 'You've got to be kidding. How could anyone think there is any viable challenge here?' " says Michael Burt, a public defender in San Francisco who tried to exclude fingerprints that implicated a client named Robert Nawi. "I think the courts felt this was way too novel to really take seriously."

In a Brooklyn case, New York v. Hyatt, during which the defense tried to use Cole as an expert witness, the court was coldly dismissive: "To take the crown away from the heavyweight champ you must decisively out-score or knock him out. Going 12 rounds will not do. What Dr. Cole has offered here is interesting, but too lacking in scientific method to even bloody the field of fingerprint analysis as a generally accepted scientific discipline."

David Faigman, a professor at the University of California's Hastings College of Law, is baffled by such logic. He recalls one case, U.S. v. Havvard, in which the court concluded that fingerprints satisfied Daubert because they'd been used in trials for so long. "Anybody who has even a minimal amount of scientific training wouldn't think that the adversarial process satisfies the testing requirement that Justice Blackmun quoted," says Faigman. "Testing means clinical testing, proficiency testing, double-blind testing. . . . The adversarial process is not about empirical testing—it's a competition."

By Plaza, fingerprinting had weathered nearly two dozen challenges unscathed. But Judge Pollak was less than impressed with the government's proof of fingerprinting's infallibility. He noted that in a previous case, U.S. v. Mitchell, an FBI survey of state crime labs had "offered scant support for the accuracy of fingerprint identification. Nine of the 34 responding agencies did not make an identification in the first instance." He also disapproved of the paucity of studies he deemed adequately peer reviewed.

Pollak was careful to emphasize that he did not wish to discredit fingerprinting entirely—"putting at naught a century of judicial acquiescence in fingerprint identification processes would be unwarrantably heavy-handed." In his January decision, he ruled that fingerprint examiners could not present "their 'opinion' that a particular latent print is in fact the print of a particular person." That would have meant no more climactic courtroom scenes in which an examiner definitively states that, yes, the print found at the crime scene belongs to the defendant.

But in his March 14 reversal, Pollak softened his stance considerably. He still knocked the FBI proficiency tests that supposedly demonstrate the accuracy of fingerprinting, and he still refuses to characterize fingerprinting as a science. Nevertheless, he concluded that he was "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." In other words, the burden lies with fingerprint critics to back up their doubts.

Defense attorneys are puzzled by the flip-flop, since the original edict merely put fingerprints on par with other brands of expert testimony. "If a psychologist testifies, the psychologist has to say, 'It's my opinion based on a reasonable degree of medical certainty,' " says public defender Grohs. "And in DNA they have data banks, and they do probability—they'll say, 'The probability of this being from somebody else is one in 20 billion,' or whatever. So why is it that fingerprint experts have been allowed to say, 'This is a match'? "

Forensic scientists, of course, were aghast at Pollak's initial ruling, which they ascribed to the defense team's skewing of evidence against the technique's reliability. They still question whether Pollak—and other well-educated judges—may harbor an ingrained bias against fingerprint examiners merely because they lack Ivy League pedigrees; in his initial opinion, the former Yale Law School dean noted that "even those who stand at the top of the fingerprint identification field . . . tend to be skilled professionals who have learned their craft on the job without any concomitant advanced academic training. It would thus be a misnomer to call fingerprinting examiners a 'scientific community' in the Daubert sense."

The experts' most venomous attacks, however, have been reserved for Cole, whom forensic scientists regard as a publicity-seeking dilettante bent on marketing Suspect Identities. They relish pointing out that the bookish Cole has zero formal training in either forensic science or law enforcement. "[Cole's] book is comprised mostly of historical accounts, related in a manner that, if anything, demonstrates the superficiality of the author's understanding of that about which he writes," wrote Andre Moenssens, a law professor at the University of Missouri at Kansas City, in an essay condemning Pollak's first opinion as "unwarranted."

"There is information out there that flies in the face of what [Cole] says," adds Joe Polski, secretary of the International Association for Identification (IAI). "He's just chosen to take the path he has." The rare mistakes that do occur, he says, are due to human frailty rather than any problem with the method. To discount the entire science because of a few foul-ups, then, is akin to dismissing aviation because a plane crashes, or junking mathematics when an eighth grader bungles a quadratic equation.

Cole, who shrugs off the personal attacks as a substitute for reasoned arguments, regards that defense with skepticism. "I think that the fingerprint community did some clever things about managing errors," he says. "There was this idea that the error would always be attributed to the practitioner and not to the method, and therefore the method is still infallible even if there's an error." In the FBI survey referred to in Pollak's January opinion, for example, the agent in charge offered a range of excuses for the nine examiners who failed to identify the prints, from "inexperience" to "insufficient time" to "attitude toward survey was not as serious as it should have been."

Despite Pollak's hedge, fingerprint experts are aware that their trade is about to come under unprecedented scrutiny. Defense bar celebrities Peter Neufeld and Barry Scheck have called on the National Institute of Justice to fund scientific studies of the technique, and next month the IAI will hold a conference at the University of West Virginia to hash out how forensic scientists should deal with the challenges. Faigman believes the controversy will compel the Justice Department to "go out and do what they should have done 100 years ago, which is collect data on the empirical validity of fingerprint technology. And my guess is that, at some level, it will be demonstrated to be valid. And it'll probably have some weaknesses, too."

Such studies could take years to complete. For people like Robert Hood, however, the fingerprint debate will have a more immediate payoff. At a pre-trial hearing in mid January, Grohs asked the court to rule out the prints. The controversy's big guns were present—Cole traveled to Colorado to testify for the defense, while the state called Stephen Meagher, chief of the FBI's fingerprint unit. The judge ruled the evidence admissible, but a mistrial was declared soon after on unrelated grounds. For the retrial, Grohs hopes to enlist the aid of James Starrs, a George Washington University law professor infamous for exhuming the corpses of Jesse James and Meriwether Lewis; he's also a noted fingerprint skeptic who has derided the technique as a "miasma."

Grohs will be on the lookout for jurors willing to consider the fallibility of fingerprints—a difficult task, given the number of Americans weaned on Matlock reruns and Agatha Christie mysteries. "We talked to [the first trial's jurors] just about fingerprint evidence, and it was hard to get them to open up," says Grohs. "They'd say, 'Well, if you have a fingerprint, then he did it.' But when we'd ask why they thought that, they'd say, 'I don't know, I guess I've seen it on TV, [or] in the movies.' Does that make it true?"

The predisposition to trust fingerprints could theoretically render any scientific attack moot. Defense experts may attack the technique as flawed, but jurors long exposed to courtroom dramas might tune out the criticism. As Arizona State's Saks puts it, if "the government expert gets up there and puts up his chart and says, 'This point matches this point, and that point matches that point' . . . then jurors will be very likely to say, 'Well, that's a match then.' "

For the sake of defendants whose freedom hinges on the veracity of some smudges, Grohs hopes that isn't the case. "Everyone's going to have to keep fighting, fighting, fighting before we get people to budge," she says. "It's kind of hard to overcome 100 years of babble."

Brendan I. Koerner is a Markle Fellow at the New America Foundation.

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