Now it's easier to ID the crooks
- By Trudy Walsh
- Feb 18, 2004
Indianapolis police have found that the Identix TouchPrint 3800 hand-scanning system has improved the accuracy of fingerprint identifications.
A biometric booking system that scans a subject's whole palm, not just the fingers, is lending a hand to Indianapolis police.
The city in 2001 received a $1.5 million matching grant from the Justice Department to upgrade its Automated Fingerprint Identification System equipment. Indianapolis used the money to buy a $3 million live-scan digital booking system from Identix Inc. of Minne-tonka, Minn.
'We already had a finger-scan system,' said Royce D. Taylor, identification section manager at the Indianapolis Police Department. 'But we wanted a system that would scan the whole palm.'
Identix and NEC America Inc. of Dallas integrated the Identix TouchPrint 3800 live-scan booking station with NEC's AFIS equipment. The city had to change the hardware design and rewrite the software.
The TouchPrint 3800 has a roller-shaped platen against which an individual presses the palm or fingers. 'Flat platens miss the curved regions of the palm,' especially the interdigital region between fingers and palm, said Frances Zelazny, director of corporate communications for Identix.
She said a white paper written by fingerprinting specialists 50 years ago recommended inking a cylindrical tube much like a paper-towel roll, and having a suspect roll the whole hand over the tube from wrist to fingertips. 'That's messy, but the same idea is behind the cylindrical platen,' Zelazny said.Data integrity questions
Finger-scanning examiners sometimes have to splice together parts of prints, missing some of the minutiae, which could lead to court questions about data integrity. Capturing the whole handprint lessens the need for splicing, Zelazny said.
People applying for a job that requires a background check are sometimes nervous and have sweaty palms during fingerprinting, she said, but criminals try to trick the system by spitting on their hands and registering only smudges. The TouchPrint 3800, which runs under Microsoft Windows or Linux operating systems, ignores sweaty palms.
If an examiner takes a partial palm print that doesn't match anything in the database, it becomes a latent print for matching against new prints. The city now sends captured prints over a secure virtual private network to the Indiana state police. The prints also go to the FBI's Integrated Automated Fingerprint Identification System.
If there is a match, Indianapolis 'can hold the person until law enforcement from elsewhere comes to pick him up,' Taylor said. 'It was monumental for us when that went into place.'
As recently as 1999, when fingerprinting specialists in the Indianapolis department wanted to check fingerprints against the IAFIS database, they had to fill out a card, mail it to the FBI and wait a month or so for the reply. Often the suspect would have fled by then, Taylor said.
The new system 'never misses,' he said. The TouchPrint 3800 scans the prints at a resolution of 1,000 dots per inch'twice the resolution required for FBI certification.
The city's NEC AFIS went live June 30. In the first six months, the Identix system identified 96 palm prints and 498 fingerprints.
'When I started working in identifications in 1989, we had no AFIS,' Taylor said. 'We had about 3.5 million fingerprints on file. To cold-search every card and look at every fingerprint is impossible. It would take two men two years at two-and-a-half hours a day to do it.'
To search now takes 25 minutes, he said. 'If those prints are in the database, it will match.'
Trudy Walsh is a senior writer for GCN.