The Green River Killer, who scattered the bodies of 49 prostitutes around the Pacific Northwest in the early 1980s, has eluded the finest minds in Washington state law enforcement. Now, they're turning to artificial intelligence to help catch such serial slayers.
The Washington state attorney general's office is currently testing neural network software designed to comb through thousands of crime reports to track down serial killers and rapists. Neural networks are computer systems designed to find patterns in data by mimicking human thought processes.
CATCH -- Computer Aided Tracking and Characterization of Homicides -- seeks patterns in the cases by comparing over 200 variables, from the weapon used to the type of torture inflicted upon the victim. The Pacific Northwest National Laboratory, which is funded by the federal government, designed CATCH.
"It's very impressive," says Bob LaMoria, program manager of the Washington attorney general's Homicide Investigation Tracking System, or HITS, database, which has amassed detailed records on some 7,000 homicides and nearly 9,000 sexual assaults.
By comparing solved murders or rapes with similar unsolved ones, it can also develop profiles of likely suspects. "CATCH can help us link cases in ways we wouldn't necessarily see," says LaMoria. "There's no way a human being can look at 7,000 cases and compare 200 fields of information."
Washington is something of a pioneer in using computer technology to track serial killers. Facing a rash of savage slayings in the 1970s, investigator Robert Keppel came up with the idea of laboriously entering information on thousands of suspects onto computer punch-cards, then the cutting-edge technology for law enforcement.
The computer churned through the information and spat out the name of a likely suspect that turned out to be correct: Ted Bundy.
Spurred by the massive Green River investigation, Keppel went on to establish the US$10 million HITS database. Only the FBI and the Royal Canadian Mounted Police currently keep violent crime databases as detailed as Washington's.
Now one of the attorney general's top investigators, Keppel is helping to test CATCH. So far, results have been mixed. CATCH has correctly grouped some known serial crimes, but has also put two murders committed by the same killer at opposite ends of its matrix.
