When the TV detectives on Miami Vice or Night Heat lift a fingerprint from a murder weapon, or find out from witnesses that the suspect had a big tattoo, it's just a matter of time before they get their man.
Not so in the real world, where fingerprints and detailed eyewitness descriptions aren't much help--unless of course the criminal should drop his wallet, containing his name and address, at the crime scene.
The challenge of detective work, especially in a jurisdiction as vast as the 110 square miles policed by the Industry Sheriff's Station, has always been akin to picking a needle from a haystack.
Lt. Larry Giger, of the sheriff's station, said the odds of apprehending an anonymous criminal in the huge district, where 7,000 vehicles and 10,000 individuals have been linked to crimes just since last May, are often laid to luck.
"It's what we call a whodunit. Who knows?," said Giger. "I sure don't know, and the chances that we'll find out are pretty small."
But all that may change, and soon.
This month, the sheriff's station will join a growing number of law enforcement agencies that are drafting the skills of a high-tech detective, a computer that can do everything from spewing out the names of previously arrested people who have distinguishing marks like tattoos, to tracking down a group of vehicles that match the color and make of a getaway car.
Under a $675,000 state grant from the Career Criminal Apprehension Program, the sheriff's station has been collecting these small bits of information on every crime committed in its 10-community district since last May, when the grant was approved.
Giger said each bit of data, ranging from whether a suspect's car had two or four doors, to whether the crime was committed at night or in the morning, will be fed into the station's new computer.
"Somewhere in this pool of information that we're feeding into the computer are the people, the career criminals, who commit an inordinate share of the crimes here," Giger said. "What we've often been unable to do, up to now, is to figure out just who they are."
Giger said most of the crimes committed in the San Gabriel Valley area this year will be the work of someone who was arrested last year or the year before, but who, for a number of reasons, is back on the streets.
The trick, Giger said, is to link clues from a breaking case to details gleaned from one of the thousands of individuals who have been arrested in the past. The task, often impossible for a deputy, is perfect for a computer.
Similar computer systems are already being used in Hawthorne, Huntington Park, Norwalk, West Covina and Whittier--a reflection of the widely held belief within law enforcement circles that the vast majority of crimes are the work of "career criminals" operating within a territory they know.
Part of the computer's value is its speed. If a deputy searched through the huge pile of 7,000 suspect vehicle descriptions that have piled up in the Industry station since last May, seeking clues for a current rash of robberies, "it would take days and days, if not weeks, to find something," said Sgt. Ron Stone, of the station's crime analysis unit.
"To do it with a computer will take me one-third of a second," Stone said. "It takes massive amounts of data and crunches it down in a hurry."
Can Spot Crime Trends
The computer will also be able to reveal crime trends block by block, or square mile by square mile. This will enable the department to begin predicting crime by area, type, and even time of day, allowing the department to assign officers to expected hot spots, Giger said.
In addition, the computer eventually will be programmed with every fingerprint taken from every arrested individual and crime scene since last May. The computer will be capable of finding prints, already in the system, that are similar to fresh prints from new cases.
At that point, said Deputy Pat Hoban, of the station's crime analysis unit, the real detective work can begin.
"The computer doesn't give you answers," he said. "It gives you possibilities. It's a big memory bank for each of us."
May Improve Usefulness
That feature may dramatically improve the usefulness of fingerprints, which officers say have proved to be nearly worthless for cracking cases.
"We take fingerprints on everything, but chances of pinning them to someone are slim and none," Hoban said.
"About the only time a fingerprint is useful is when you remember an earlier arrest, and you have reason to believe that he was the same dirt-bag this time around. Otherwise, that fingerprint would go in the file and never be looked at again."
Hoban said that cracking the highly publicized Night Stalker case, in which a fingerprint left at a crime scene was computer-matched by the Orange County Sheriff's Department to suspect Richard Ramirez, was "an incredible piece of luck."
"They just got that (computer) two weeks earlier," Hoban said.