Just when the Green River Killer thought he could get away, DNA saved the day. "COLD CASE: CLOSED"
|In the 1980s and 1990s, a faceless killer stalked young women in the Seattle-Tacoma area. Dozens of women, mostly prostitutes, eventually disappeared, sometimes only a few days apart, sometimes only once or twice a year. The killer had a consistent modus operandi: he would rape the women and strangle them with his hands or a ligature...The police compiled a short list of suspects, including Gary Ridgway, a factory worker. But DNA testing was still in its infancy in the 1990s, and since officers lacked enough physical evidence to tie Mr. Ridgway to the crimes, they were unable to arrest him...In 2001, a one-two technological punch brought the case back to life. Forensic investigators decided to re-examine evidence compiled years before with the help of two new modes of DNA analysis: the polymerase chain reaction (P.C.R.) test and the short tandem repeat (S.T.R.) test. Together, these tests proved indispensable because they allowed the scientists to sequence and copy very short fragments of DNA taken from crime scenes...After Dr. Himick and her colleagues completed new DNA profiles from three victims, they compared them with DNA extracted from a piece of gauze Mr. Ridgway had chewed on in 1987. Dr. Himick was floored: the DNA profiles taken from the victims matched .|