For almost a century, American courts have thought about fingerprints the way children visualize snowflakes: No two are exactly alike. So most judges, jurors, and lawyers came to trust that fingerprints left at crime scenes match the right suspects to their misdeeds. But in his new history of criminal identification, Simon Cole questions whether fingerprinting deserves its hallowed reputation.
"Suspect Identities" appears just as defense attorneys throughout the country are launching the first serious legal attack on fingerprinting since its acceptance by courts nine decades ago.
Cole traces criminal identification back much further, from the branding of prisoners to modern DNA analysis. He shows how fingerprints emerged in the 19th century as a way for jailers to identify repeat offenders and for white bureaucrats to sort out Indian pensioners or Chinese immigrants whom they couldn't tell apart.
Fingerprinting initially competed with anthropometry, an identification technique that measured body parts ranging from arm span to cheek width. Both methods required intricate classification systems, which Cole describes in sometimes numbing detail.
Fingerprinting eventually won out, offering the aura of new technology without anthropometry's more complicated calipers and gauges.
Only later did police departments use the finger's distinctive arches and loops as a forensic tool in solving crimes. But identifying a smudged or distorted fingerprint fragment found at a crime scene is much harder than matching two sets of perfect prints taken by a technician.
Cole suggests fingerprint examiners never proved two fingerprints can't be alike. Nor did the decentralized American criminal justice system ever develop a uniform standard for how similar a fragment must be to fingerprints on file.
Instead, fingerprint examiners relied on their subjective expertise and pointed with assurance to the millions of fingerprints collected in which no two people provided identical prints.
By the 1920s, Cole says the moment for challenging forensic fingerprinting identification had passed. Courts simply ruled no evidence was required to prove the science of fingerprinting.
In the decades since, Cole says, judges, jurors, and defense attorneys "continue to demonstrate boundless faith" in fingerprint evidence even as problems brew beneath "the imposing veneer of scientific and legal authority."
He aims much of his criticism at the fingerprint examiners. Early on, he claims a self-anointed group of professional fingerprinting examiners established their exclusive authority to interpret fingerprint evidence and discouraged disagreement. He highlights more recent examples of examiners' fabrication and incompetence.
Criminal defense attorneys are now challenging fingerprinting under a 1993 United States Supreme Court decision that made federal trial judges the gatekeepers of scientific evidence. Judges must screen expert testimony before trial and weed out the junk. (Cole, as he briefly notes in the book, was enlisted in one such case to fight against the admissibility of fingerprint expert testimony.)
The Justice Department has ordered studies to validate crime-scene print identification and establish standardized procedures for examinations. Courts aren't budging, rejecting a dozen fingerprint challenges in the last two years. One federal judge called fingerprinting the "very archetype of reliable expert testimony."
It seems a bit premature for Cole to suggest the credibility of fingerprinting might soon crumble or wind up on "the junk-heap of pseudo-science."
Seth Stern graduated this month from Harvard law school.
(c) Copyright 2001. The Christian Science Monitor