Los Angeles ? Susan Atkins, the former Charles Manson follower who confessed to killing pregnant actress Sharon Tate during a murderous rampage in 1969, has a terminal illness and has asked for compassionate release from prison in her final days, authorities said Thursday.

Atkins, 60, who has been incarcerated at the California Institution for Women at Frontera for 37 years, has been held longer than any other female inmate in state history.

Department of Corrections spokeswoman Terry Thornton declined to specify the nature of her illness.

“She is very ill” and has been hospitalized, said Thornton.

“Her condition is very serious and her prognosis is poor,” she said.

Thornton said a doctor determined that Atkins has less than six months to live, which could make the application for release futile because of the length of the process.

“Sometimes inmates being considered for compassionate release die during the process,” Thornton said.

Atkins was the most notorious of the three women charged with Manson in the grisly slayings of Tate and six other people in the summer of 1969. She enabled authorities to break the case after it had remained unsolved for three months by confessing to a cellmate when she was arrested in an unrelated crime. It was Atkins who disclosed that the Manson Family, a rag tag cult living in a ranch commune, had been responsible for the murders.

Her statements led police to a Death Valley hideout where they found Manson and other members of his cult. Her lawyer later complained that prosecutors broke a promise to her of leniency for breaking the case.

In a sensational 10-month trial, Atkins, Manson and co-defendants Patricia Krenwinkel and Leslie Van Houten maintained their innocence. But once they were convicted, the women took the stand in the penalty phase and confessed in graphic detail to the killings.

Atkins calmly recounted her own role in stabbing the pregnant Tate, who pleaded for the life of her unborn baby.

In her chilling testimony, she said, “I don’t know how many times I stabbed her and I don’t know why I stabbed her…. She kept begging and pleading and begging and pleading and I got sick of listening to it, so I stabbed her.”

She said the killings were done under the influence of hallucinogenic drugs.

“I was stoned, man, stoned on acid,” she testified.

She expressed no remorse until years later when, at her parole hearings, she apologized. But she also suggested she may have exaggerated her role during the trial and that she did not actually kill Tate. The claim was dismissed by prosecutors as self-serving.

At the end of her trial testimony, she said, “I feel no guilt for what I’ve done. It was right then and I still believe it was right.”

A psychiatrist who examined her at the time said she was mentally ill. Jurors heard about her troubled childhood and the trauma of losing her mother at a young age to cancer.

She and the others were sentenced to death but their terms were commuted to life in prison when the U.S. Supreme Court briefly outlawed the death penalty in the 1970s.