(CBS/AP/KIRO) SEATTLE - Green River Killer Gary Ridgway pleaded guilty Friday in Washington state to the murder of a 49th victim, Becky Marrero.
On Dec. 21, a human skull was found by teenagers in a wooded area, reports CBS affiliate KIRO. Investigators also found bones while combing the area. The remains were later identified as those of Marrero.
Ridgway already is serving 48 life terms at the Washington State Penitentiary at Walla Walla. He entered his plea Friday at his arraignment on a murder charge at the King County Regional Justice Center in the Seattle suburb of Kent. He was charged Feb. 7.
The Sheriff's Office said Ridgway was questioned extensively in 2003 about Marrero's disappearance. An official said though Ridgway had confessed to killing Marerro in 2003, her remains had not been found and Ridgway was unable to provide sufficient details to charge him with her murder.
In a plea agreement made by late King County Prosecutor Norm Maleng in 2003, Ridgway agreed to plead guilty to any future cases in which his confession could be corroborated with reliable evidence uncovered by investigators. In return, Ridgway was spared the death penalty.
Marrero's sister, Mary Marrero, spoke in court about the loss of her sister and the effect it had on herself and the victim's daughter, according to CBS affiliate KIRO.
"The day she came up missing, I wanted to kill myself," said Mary Marerro. "It's been a long 29 years wondering every day what happened."
Mary Marrero said her family was finally able to put Marrero to rest on Feb. 5, after her remains were found in December 2010.
Then she expressed anger that Ridgway was allowed to live.
"What does it take to get the death penalty in Washington? I don't agree with the plea deal to spare his pathetic life," she said.
"He's worthless and he's not going to give any more up. He is a waste of society and a waste of space. If I had one more thing to tell you today, it would be 'kill him,'" said Mary Marrero.
The 20-year-old Marrero was last seen on December 3, 1982, when she left a motel room at South 168th and Pacific Highway South, the Sheriff's Office said.