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Monday, June 02, 2008

Ind. Law - "Local crime scene investigators debunk some myths about their work"

A story today in the Evansville Courier & Press reminds us that police work is not like CSI. Gavin Lesnick reports that the show often heightens expectations. Take fingerprints:

[Tony Walker, a 16-year veteran of the Evansville Police Department's crime scene unit] finds himself at trials all the time, he said, explaining why there are no fingerprints from one crime or another.

People seem to expect they can be lifted from any scene, but a wide range of factors affect the process: the moisture or lack of moisture on a hand, the texture of the surface, the frequency it's been touched (doorknobs pose problems) and the movement of the hand all can render prints unuseable.

"There are just so many variables," said Bill Schafer, another member of the unit.

Cars are particularly problematic. Finding a good print on a steering wheel is a "one-in-a-million" shot, Walker said, and taking them off other interior surfaces is possible but expensive and damaging.

The exteriors actually hold prints well, but such evidence won't stand up in court.

"The defense attorney will say maybe he touched the car," Schafer said. "But that doesn't mean he stole it."

Once back from a scene, the local crime scene unit does input their fingerprint data into a computer, like on "CSI," but it's not quite the same.

Unlike in "CSI," in which the Automated Fingerprint Identification System often turns up a single, definitive match, the real system is rarely, if ever, so specific. It will match up prints with several potential suspects or other investigations and return a list of possible cases. Eight-hundred people have been matched through the system since it was purchased five years ago.

But the computer is just the first step.

From there, the crime scene investigator must compare the prints by hand — painstakingly measuring and analyzing them before determining if there really is a match.

There's no room for error. In court, the first question lawyers often ask is if they have ever made a false identification.

Posted by Marcia Oddi on June 2, 2008 08:37 AM
Posted to Indiana Law