Nicknamed "The Scorecard Killer," Randy Steven Kraft prowled the nation's highways from 1971 to 1983. Kraft was a soft-spoken computer consultant who traveled frequently on business. On highways, the sexual predator picked up young male hitch-hikers, including several U.S. Marines. Doping his passengers with Valium and liquor, he raped, tortured, and killed them, often in his car, before dumping their bodies by roadsides. In 1989, an Orange County, California, jury convicted Kraft of sixteen murders, but authorities believed that the real total was many times higher. Their estimate was based on a bizarre list. Written in a code that Kraft never divulged, prosecutors alleged that it was a scorecard, a personal log of dozens of sexual murders.

Quite by accident, the California Highway Patrol made a hideous discovery in May 1983. Noticing a vehicle weaving in traffic, officers stopped a Toyota with two men it. The 38-year old driver, Kraft, failed...