Claim: Gary Ridgway was a serial murder.

Gary Leon Ridgway -LRB- born February 18 , 1949 -RRB- is an American serial killer known as the Green River Killer . He was initially convicted of 48 separate murders and later confessed to nearly twice that number . As part of his plea bargain , an additional conviction was added , bringing the total number of convictions to 49 , making him the most prolific American serial killer in history according to confirmed murders . He murdered numerous women and girls in Washington State during the 1980s and 1990s . Most of his victims were alleged to be sex workers and other women in vulnerable situations , including underage runaways . The press gave him his nickname after the first five victims were found in the Green River before his identity was known . He strangled the women , usually by hand but sometimes using ligatures . After strangling them , he would dump their bodies in forested and overgrown areas in King County , often returning to the dead bodies to have sexual intercourse with them .   On November 30 , 2001 , as he was leaving the Kenworth truck factory where he worked in Renton , Washington , he was arrested for the murders of four women whose cases were linked to him through DNA evidence . As part of a plea bargain wherein he agreed to disclose the locations of still-missing women , he was spared the death penalty and received a sentence of life imprisonment without parole .