DNA Evidence That Unmasked the Green River Killer

In 2001, authorities arrested Gary Ridgway for loitering to solicit a sex worker—a routine bust that would unravel one of America's most devastating serial murder cases. What began as a minor charge evolved into murder convictions for 49 victims spanning nearly two decades, thanks largely to DNA evidence that had been painstakingly preserved since the early 1980s.

When the first victim, 16-year-old Wendy Coffield, was discovered in the Green River near Seattle in July 1982, investigators had no idea they were dealing with a serial killer. Bodies continued appearing throughout the 1980s. By 1984, authorities formed the Green River Task Force with 55 dedicated detectives, but without modern forensic tools, the investigation stalled. Ridgway, a painter at the Kenworth Trucks manufacturing plant, initially escaped suspicion despite police interest.

On April 8, 1987, officers searched Ridgway's house and collected a saliva sample. This seemingly routine procedure would ultimately prove crucial. The sample was stored for future DNA testing—a prescient decision, given that the forensic technology needed to analyze it didn't yet exist.

The breakthrough came in the late 1990s and early 2000s, when advances in DNA profiling technology—specifically STR PCR (short tandem repeat polymerase chain reaction) analysis—made it possible to extract usable genetic profiles from minimal biological evidence. Forensic analysts Beverly Himick and Jenifer Smith, working from autopsy swabs collected from victims found together in the Green River in summer 1982, generated a male DNA profile despite the samples' age and degradation.