Science lends a helping hand to law enforcement

Former St. Mary Parish Sheriff David Naquin was on hand at the weekly meeting of the Franklin Rotary Club Tuesday to deliver an informative presentation as well as a message for the audience…if criminals leave behind fingerprints, law enforcement has a distinct advantage in identifying them and bringing them to justice.
Naquin, who practiced law enforcement for 37 years and is an expert fingerprint analyst, gave a slide show presentation before the audience that provided them with just a glimpse of what it takes to match something as unique as a fingerprint. And according to Naquin, they are truly unique.
Even with over 7 billion people alive today, Naquin said there have never been two fingerprints that are identical and that’s what makes it possible for law enforcement to match them so accurately.
And while Naquin said Hollywood and television crime dramas depict quick and easy fingerprint identification with fancy computers such as the Automated Fingerprint Identification System (AFIS), the truth is a sharp human eye and analytical brain are still called upon in most cases for a positive identification. Naquin also said there has yet to be a computer invented that can stand up and take an oath in a courtroom.
“I know everyone watches those shows,” Naquin said. “I can tell you, in reality, it does not happen like that. The second reason they still need people like me is they have yet to find a machine that can come to court and testify. So that’s why they keep guys like me around. A machine can’t get cross-examined or questioned.”
Naquin said since his initial certification in 1974, he has testified over 30 times in court regarding fingerprints. He also said the accuracy involved with fingerprint analysis was staggering. According to Naquin, DNA analysis is accurate, on average, over 98 percent of the time. But he said because no two fingerprints are alike, even on an individual’s same hand, the odds of a false positive are simply zero.
“What you are going to see is 100 percent,” Naquin said. “It either is or it isn’t. There’s no in-between. There’s no ‘kinda’. There’s no ‘oh it’s close.’ There’s none of that. No two have ever been found to be identical. A lot of people’s are similar but none are identical. Think about how many billions of fingerprints there are in the world and no two have ever been found to be the same. It’s really amazing.”
Naquin said there were three basic types of fingerprints, each with a small set of subgroups. The three types are loop, whirl and arch. He said however, after identifying the type of print pattern, identification doesn’t stop there.
“I have to find between eight and ten points to say that two prints are the same,” Naquin said. “It just depends. I’ve done as many as 30 (points of identification) but it just depends on the print. When you find a point of identification, it has to be on both prints in the exact same spot. It can’t be a little off. If I find six and I get to seven and it’s a little off, it’s not him. I could not make that identification.”