The man dubbed the "Happy Face Killer" has been sentenced to life in prison for committing a murder for which two others have already been imprisoned for five years.
Keith Jesperson, 40, pleaded no contest to strangling Taunja Bennett in 1990. Under a plea agreement, he will serve at least 30 years.
Jesperson told Presiding Circuit Judge Donald Londer on Thursday that he met Bennett, 23, at a tavern in January, 1990.
He said the two began to have sex at his house that night but got into an argument. He hit Bennett, then knotted a rope around her neck until she died.
He dumped the body in an isolated area near the Columbia River on Oregon's northern state line.
Jesperson told the judge he did not know Laverne Pavlinac and John Sosnovske, who were sentenced to life in prison in 1991 for the slaying.
Prosecutors asked a judge to free the pair last week after Jesperson led investigators to Bennett's purse near where the body was found and gave details about the crime that only the killer would know. But Circuit Judge Paul Lipscomb said there was insufficient evidence and ordered them to stay in prison. He said Pavlinac, 62, and Sosnovske, 42, could request a hearing and present additional evidence, such as Jesperson's plea.
Pavlinac had told jurors during her trial that she made up the story about how she and her abusive boyfriend raped and strangled a woman. She said she told the story in an attempt to get Sosnovske to leave her alone.
But prosecutors played the jury a tape of her confession, and she was convicted of murder and sentenced to life in prison. Sosnovske pleaded no contest to murder to avoid the death penalty, and was also sentenced to life.
The rape allegation surfaced only in Pavlinac's story to police. Jesperson was not charged with rape and did not mention it in his account of the crime in court.
Jesperson, an interstate trucker, is known as the Happy Face Killer because he has drawn smiling faces atop neatly printed letters to the media claiming that he has killed eight women in five states.
He is being held in Vancouver, Wash., awaiting sentencing for kidnaping, raping and strangling a woman in March.