In the 1980s and ’90s, over fifty women in the Seattle-Tacoma, Washington, area were murdered. Most of the victims were prostitutes or teen runaways, and most of the bodies were dumped in or near the Green River. Dubbed the Green River Killer, the murderer was unknown until science managed to catch up to crime.
In the early 1980s, while performing autopsies on the victims, pathologists and medical technologists were able to recover small amounts of DNA in semen left behind by the killer. These were retained as evidence, but then-current scientific techniques proved worthless, since there wasn’t enough material for testing.
Gary Ridgway, who was arrested in 1982 on a prostitution charge, was a suspect in the Green River killings, but there wasn’t any evidence to formally link him to the crimes. In 1984, he passed a polygraph test. In 1987, while searching his home, the King County Sheriff’s department took a saliva sample from Ridgway.
By March 2001, improvements in DNA typing technology had identified the source of the semen on the victims’ bodies. In September 2001, the lab received results: they were able to get a comparative match between the DNA in that semen and the DNA in Ridgway’s saliva. A warrant was issued for his arrest.
The DNA results linked Ridgway to three of the four women listed as victims in his indictment. Sperm samples taken from one of these victims, Carol Ann Christensen, were so conclusive that not more than one person in the world, excluding identical twins, would exhibit that particular DNA profile. Ridgway was charged with three more murders after microscopic paint evidence found with the bodies matched paint at his workplace. In return for confessing to more of the Green River murders, Ridgway was spared the death penalty and is currently serving forty-eight life sentences with no possibility of parole.