In the 1991 movie The Silence of the Lambs, a frustrated Jodie Foster tells an FBI colleague that if there had been a spatial pattern to serial killer Buffalo Bill's murders, the computer would have picked it up. Kim Rossmo remembers smiling as he watched that scene. He knew that no such computer program existed - but he was busy inventing it.
Five years later, in his office at Vancouver Police Headquarters, Rossmo unveiled the real thing: Orion, a software program for hunting serial criminals. "There are 79 crimes on this screen," says the detective-inspector, pointing to a Sun Microsystems UltraSPARC that displays a map of the Vancouver area. Rossmo is using the career of the Paper Bag Rapist - a notorious criminal who wore masks when assaulting victims - to demonstrate how Orion can help detectives figure out where serial criminals live, often within a few hundred yards.
At first glance, the crime sites on the screen look like a random collection of dots scattered all over the map. As the program goes to work, however, a pattern emerges. "The computer performs 790,000 different calculations," says Rossmo, who began developing the program in the early 1990s while earning a doctorate in criminology and working night shifts on the skid row beat. Using data on the typical distance traveled to commit a crime, the computer calculates the probability of any given point on the map being the offender's home - and then repeats the process for all the other points on the map and every crime site. "It produces a map that expresses the probability of offender residence," Rossmo says. With a couple of keystrokes, he calls up a street plan with a red dot over a single square block - an area that includes the apartment in which the Paper Bag Rapist was apprehended.
Orion is being tested in serial arson, murder, rape, and other investigations, often with spectacular results. In one case, the program pinpointed the work site of a man who was robbing credit unions during his lunch break. In Ontario, Canada, Orion picked out a sex killer's neighborhood from an area of hundreds of square miles, reducing a database of 3,200 names to a handful of likely suspects.
Rossmo has created a private company to develop and market the Orion system. In the meantime, he's been asked to demonstrate how Orion can crack unsolved cases in the files of Scotland Yard, the Royal Canadian Mounted Police, and the FBI Behavioral Science Unit - the inspiration for The Silence of the Lambs.
