Massachusetts Supreme Judicial Court to hear arguments on banning fingerprint evidence
By Jonathan Saltzman, Globe Staff | September 5, 2005
For more than a century, a fingerprint match has been considered nearly unimpeachable evidence in a criminal case. Trace a latent print at a crime scene to the fingertip of a suspect, goes the conventional wisdom, and you've got the bad guy.
But the bedrock forensic science has been under intense scrutiny recently as a result of a series of high-profile errors by fingerprint examiners around the country, one of which led to the imprisonment of an innocent Boston man after a false match tied him to the shooting of a police sergeant. Some critics say fingerprint analysis isn't even a science.
Now the controversy is coming before the highest court in Massachusetts. The Supreme Judicial Court is scheduled to hear arguments Wednesday about whether to quash key fingerprint evidence in the case of Terry L. Patterson, who is being retried in the 1993 slaying of a Boston detective.
In addition, Patterson's lawyer in the case, John H. Cunha Jr., wants the SJC to do what no other state supreme court has done: bar fingerprint analysis from being presented in all criminal trials until it is subjected to rigorous scientific scrutiny and proven reliable.
Cunha, who has enlisted 15 scientists and scholars to bolster his argument, said fingerprint analysis has never been systematically studied for its reliability. It lacks uniform standards for how many characteristics must be present in a latent print before analysts can declare a match, he said, nor are there statistical models to calculate how often analysts err. Instead, its reputation for infallibility approaches an article of faith.
''That's the sense we all had of it from watching 'The FBI' with Efrem Zimbalist Jr. in the '60s: 'They've got the fingerprint? Oh, they've got the guy,' " Cunha said. ''But when people started looking at it, it became very clear that it's a house of cards."
Suffolk prosecutors, who are opposing the request to ban the use of prints as evidence, counter that fingerprint analysis withstands scrutiny every day in criminal cases. Mistakes are infinitesimal and always the result of human error, they say, making fingerprint analysis one of the most reliable crime-fighting tools ever developed.
Perhaps the most persuasive argument in favor of the reliability of fingerprints, according to papers filed by Suffolk District Attorney Daniel F. Conley's office, ''is the fact that in the more than one hundred years in which fingerprint examinations have been conducted, there has never been a single reported instance of two fingerprints being identical."
The outcome of the case could have broad implications. Even if the court rejects Cunha's blanket request to block fingerprint evidence at trials, it could take a more modest step -- say, requiring that juries be instructed that the evidence is not fool-proof.
Fingerprints, imprints left on a surface by patterns of ridges on the pad of a human finger, have been used as a form of criminal identification since the early 1900s. Because no two humans, not even identical twins, have ever been found to have identical prints, fingerprint analysis quickly became the gold standard of criminal forensics after Scotland Yard established the first British fingerprint lab in 1901.
Today, the FBI has more than 36 million individuals' prints on file, says the bureau website. It is the largest collection in the world.
But fingerprint evidence has received a more skeptical look in recent years, in part because its acceptance came without any of the rigorous questioning that accompanied the emergence of DNA evidence in the 1990s, said David M. Siegel, a New England School of Law professor who helped write a friend-of-the-court brief on behalf of the scientists and scholars.
When courts began grappling with whether to admit DNA evidence -- promoted as genetic ''fingerprinting" -- they first considered a host of questions, including how a DNA match is defined, how often laboratories make mistakes, and how many individuals have certain genetic traits.
''Instead of accepting something because it's always been done this way, [DNA evidence] was accepted because it demonstrated its validity and the reliability of the methods by which it's produced," Siegel said. ''Those things just haven't been done for fingerprints."
There were two high-profile misidentifications last year.
In January 2004, Stephan Cowans of Roxbury was exonerated in the 1997 gunshot wounding of Boston police Sergeant Gregory Gallagher after law enforcement officials acknowledged that a thumbprint on a glass mug found near the crime scene had been misidentified as his. Cowans had spent 6 1/2 years in prison. In the wake of the blunder and a scathing critique of the police department's fingerprint unit, the city shut down the operation until it could be overhauled. Cowans was exonerated and freed.
Then in May of last year, Brandon Mayfield, an Oregon lawyer, was arrested and jailed for two weeks after FBI experts mistakenly linked his fingerprint to the terrorist train bombing in Madrid that killed 191 people two months earlier -- even though he said he had never been to Madrid.
Spurred by the Cowans debacle, Cunha renewed a request that fingerprint evidence be quashed in the case against Patterson, who is being held without bail while awaiting a retrial in the 1993 murder of a Boston police officer.
Patterson and a friend from Dorchester were convicted at separate murder trials in the slaying of Detective John J. Mulligan, who was shot five times in the face as he sat in his Ford Explorer while on a paid detail in a Roslindale parking lot. But the SJC overturned Patterson's conviction in 2000, ruling that his lawyer should have removed herself from the case and testified as a defense witness when it became clear she had information that disputed police testimony.
Cunha wants to block crucial fingerprint evidence used in the first trial from being reintroduced at the retrial because of what he calls a flagrant lack of standards in print analysis. A Boston police sergeant testified at the first trial that four latent fingerprints recovered on the driver's side window of Mulligan's SUV belonged to Patterson. But he reached that conclusion, Cunha said, by adding up matching ''ridge characteristics" from three fingers -- six on one, two on another, and five on a third -- an approach Cunha last year described as haphazard and ''crazy."
The prints were the only physical evidence tying Patterson to the crime.
Cunha said last week that the sergeant added the matching characteristics because there weren't enough points of similarity on each fingertip. Critics of fingerprint analysis note that the number of points needed to make a match varies from police department to police department, giving rise to what Siegel described in his brief as a ''knows it when he sees it" approach for fingerprint analysts.
That lack of scientific rigor is precisely what troubles Simon A. Cole, an assistant professor of criminology at the University of California at Irvine and a scholar cited in Siegel's friend-of-the-court brief.
''I'm not saying [fingerprint analysis] isn't useful," he said in an interview. ''It's just that we don't know how useful it is."
But Conley's office counters that Superior Court Judge Margaret Hinkle was right last fall when she concluded that fingerprint analysis -- including comparisons involving several fingerprints from the same hand, as in Patterson's case -- meets the scientific standards needed to introduce it as evidence. It is that ruling that Cunha and prosecutors both want the SJC to review.
Neither Suffolk prosecutors nor Cunha are predicting how the SJC will rule.
Jonathan Saltzman can be reached at jsaltzman@globe.com