Saturday, April 21, 2012

Fingerprint analysis under scrutiny

Fingerprint evidence is a staple of the American criminal justice system. The analysis of fingerprints evidence is being questioned. While fingerprint analysis is one of the most valuable and frequently applied investigative tools, its accuracy has not been scientifically defined, according to the Washington Post.

FBI examiners claimed until recently that they can match fingerprints to the exclusion of any other person in the world with 100 percent certainty using a method with an error rate essentially of zero. The academy report found that assertion was “not scientifically plausible” and had chilled research into error rates.

In 1999, a Justice Department official, Richard Rau, told a federal court that the department delayed such a study because of the legal ramifications. As recently as last year, Pennsylvania State University researcher Cedric Neumann was denied a department grant to determine potential fingerprint error rates using closed cases, repored the Post.

A person familiar with the episode blamed a polarized climate in the adversarial legal system, saying, “Few agencies in the forensic-science community want to be the first ones associated with an error rate.” The person spoke on the condition of anonymity to discuss sensitive federal research funding decisions.

Meanwhile, errors occur. In 2004, DNA for the first time exonerated a person convicted with a fingerprint match and, separately, the FBI made its first publicly acknowledged fingerprint misidentification. Brandon Mayfield, a Portland, Ore., lawyer, mistakenly was arrested in connection with the terrorist train bombings in Madrid that killed 191 people. The FBI apologized.

Since then, the Justice Department has begun research to try to quantify how complete a fingerprint must be to properly declare a match; how different conditions may affect the reliability of examinations; whether computers can do such work; and how to present forensic testimony about probabilities to judges and juries. The FBI has also required “blind verification” of results by agents unfamiliar with initial examinations, reported the Post.

The bureau said that skilled analysts are extraordinarily accurate, at least when they know they are being tested. An FBI study with Noblis Corp. last year found that when 169 examiners compared thousands of fingerprints and decided there was enough information to declare a match or not, they were correct 99.8 percent of the time.

Still, the Mayfield case highlighted the need for research into real-world conditions. A 2006 study by a London-based scientist, Itiel E. Dror, asked experts to analyze fingerprints that, unbeknownst to them, they had analyzed earlier in their careers. This time, however, examiners were given biasing statements, such as that a suspect had confessed or that a suspect was locked up at the time of the offense. In 16.6 percent of cases, examiners reversed earlier judgments, reported the Post.

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