Gary Ridgway already is serving 48 life terms at the Washington State Penitentiary in Walla Walla. He entered his plea on a murder charge at the King County Regional Justice Center in Kent, a Seattle suburb.

Ridgway, who has been dubbed the Green River Killer, confessed to killing Rebecca "Becky" Marrero in 1982 as part of a 2003 plea deal that spared him the death penalty.

 Ridgway, who was a commercial truck painter, has been convicted of 48 murders and confessed to or been suspected of dozens more. Several victims were dumped in or posed along the Green River.

He preyed upon women and girls at the margins of society — runaways, prostitutes and drug addicts strangled in a spree that terrorized Seattle and its south suburbs in the 1980s.

Marrero, a 20-year-old mother, (right) was last seen when she left a motel in 1982.

Prosecutors originally declined to charge Ridgway in Marrero's death in 2003 because he was not able to provide conclusive evidence that he killed her. The plea deal required him to plead guilty to future King County charges based on new evidence.

Marrero's remains were discovered Dec. 21 when teenagers found a skull in a ravine at Auburn, south of Seattle. They were found 100 feet from where investigators found another of Ridgway's victims, Marie Malvar, in 2003.

 Ridgway, who turned 62 on Friday, was charged with murder on Feb. 7. He was brought from the state prison for the arraignment, where he sat handcuffed and shackled around his legs.

After Ridgway entered the plea, Marrero's sister, Mary Marrero, told county Superior Court Judge Mary E. Roberts that the family had agonized for 29 years, wondering what happened to her.

"I don't agree with this plea deal to spare his pathetic life," she said in a halting voice, as Ridgway turned in his chair to face her and two other family members at a lectern. "It makes me sick to my stomach that he beat the system."

Ridgway, she said, knows where all his victims are and what he did to them. She called them "his trophies."

She told the judge, "If I had one thing to ask today, it would be to kill him." (Marrero's mother, who stood by as her daughter spoke, is pictured at left.)

Ridgway rose and began to apologize to the family, but was cut off by a man in the audience who shouted, "Shut your mouth."

"I'm sorry you had to wait this long for some truth and some justice," Roberts said to the family.

The judge told Ridgway that in his case, "I can find no compassion," then sentenced him to a 49th consecutive life term.

Ridgway was arrested in 2001 after advances in DNA technology enabled authorities to link a saliva sample he gave authorities in 1987 to some of the bodies. He pleaded guilty two years later, agreeing to help authorities locate as many remains as possible.

He is serving life without release in solitary confinement at the state prison, where he's allowed out of his cell one hour a day four times a week.