For decades, detectives have known that the answer to solving a crime can lie in the palm of someone's hand.
Palm prints make up about one-third of all prints technicians lift from crime scenes, according to estimates. But until this year, unlike fingerprints, there was no easy way to compare them.
Los Angeles County's law enforcement agencies have just taken a leap forward with delivery last month of a computer system that gives it one of the nation's largest palm-print databases.
Investigators now can compare a palm print with 250,000 others from arrestees in minutes.
The $15-million Cogent Automated Palmprint and Fingerprint Identification system can also compare a fingerprint with a database of 80 million others drawn from 4 million arrestees.
It was Cogent technology that allowed the Department of Homeland Security's immigration wing to identify the suspects accused in the Washington, D.C.-area sniper case.
The fingerprints of Lee Boyd Malvo, a Jamaican native, were in the old Immigration and Naturalization Service's database, a Cogent system.
When detectives entered those lifted from an Alabama robbery allegedly committed by the snipers, the system provided a match.
"We have had hits on a murder, a burglary and a carjacking already, and it's only been up a couple of weeks," said Sheriff's Sgt. Larry Bryant, who oversees the Los Angeles County Regional Identification System, which serves law enforcement agencies across the county.
Bryant emphasized that the system is still in the testing phase.
"Up until now, the only way we'd use palm prints was when someone gave us a name to do comparisons," Bryant said. "This [new system] requires just a small portion of the palm from a crime scene."
In the first two weeks of operation, the system generated 80 matches, mostly of fingerprints.
The hits came from an analysis of prints that had earlier been submitted to a database maintained by the state of California, which local police agencies traditionally used without results.
"The system is a double-edged sword. With an increased number of suspects, you have to have the resources to review those results," said Sheriff's Capt. Chris Beattie, head of the department's Scientific Services Bureau.
The computers identify possible matches. But it is a technician using actual prints who must make the final determination, Beattie said.
Britain's Scotland Yard first used fingerprints in 1902 to obtain a conviction. But it was not until the 1970s that automated fingerprint comparisons came into use.
What is revolutionary about the new system is that it can check so many prints so quickly in comparison to the prior generation of technology, experts said.
Wally Briefs, senior vice president of South Pasadena-based Cogent Systems, which pioneered some of the breakthrough software, said older systems limited what could be reviewed and did not tackle palm prints, which are larger and would take too long to compare.
"It used to take an entire room of computers to review this much data," Briefs said. "There is a potential to turn around the data and produce a suspect within minutes."
In one case this year, Briefs said, a Cogent identification system in another city was able to identify the deteriorated body of a woman found in a streambed based on a tiny piece of her palm recovered from the scene.
"If you think of someone gripping a knife, they use the palm," said Briefs, a former detective and crime scene technician. "When they handle a gun, it's the palm. When they open a car door, it's the palm."
With technology advancing, the level of accuracy also is improving. As part of the contract, the county required the new system to have an accuracy rate of more than 99%. Bryant said the new system also searches every image in the database.
Cogent's software converts scanned prints into digital form, then compares them to its library.
When converting the image, the software identifies specific points of data as match points, and then processes them using an algorithm that assigns them a value that can be compared with existing data.
Countywide, there are 29 terminals in use by law enforcement agencies for comparing latent prints with those in the system. There are 165 places at which prints can be scanned directly from a human hand into the Cogent database. Bryant said the new system is financed by penalties assessed on convicted criminals and a $1 fee on each vehicle registration.
Los Angeles County's new system is not unique, but it is cutting edge. Britain's police agencies use a similar Cogent system.
The New York Police Department last month put online a similar system. Ontario police pioneered its use in California on a smaller scale three years ago.
During the Salt Lake City Winter Olympics, Cogent, along with another company, provided security personnel with mobile scanners connected to a fingerprint database.
"It's yet another technological boost for law enforcement," said Dist. Atty. Steve Cooley.