(CNN) -- Former "Manson Family" member Susan Atkins, who stabbed actress Sharon Tate to death more than 40 years ago and now is terminally ill, was denied parole Wednesday, prison officials said.
Susan Atkins, shown here after her indictment in the Manson murders, was denied parole again Wednesday.
The parole hearing was the 13th for Atkins, 61, who is battling terminal brain cancer. Held at the Central California Women's Facility in Chowchilla, California, the hearing stretched to more than six hours.
The panel set another hearing for Atkins in three years, said Michele Kane, spokeswoman for the California Department of Corrections and Rehabilitation.
Atkins was 21 when she and other followers of Charles Manson participated in a two-night rampage that left seven people dead and terrorized the city of Los Angeles in August 1969. She and the others -- Manson, Leslie Van Houten, Patricia Krenwinkel and Charles "Tex" Watson -- were initially sentenced to death in the slayings of five people, including Tate, and two additional deaths the following night.
Their sentences were automatically commuted to life in prison when the Supreme Court struck down the nation's death penalty laws in 1972. Watch Atkins, victims' kin speak »
By her own admission, Atkins, known as Sadie Mae Glutz within the Manson family, held Tate down as she pleaded for mercy, and stabbed the actress 16 times. Tate was eight months pregnant. In a 1993 parole board hearing, Atkins said Tate "asked me to let her baby live. ... I told her I didn't have any mercy on her."
After killing Tate, according to historical accounts of the slayings, Atkins scrawled the word "pig" in blood on the door of the home Tate shared with her husband, director Roman Polanski. Polanski was not home, but three of Tate's house guests were also slain by the killers, as was a teenager who was visiting the home's caretaker in his nearby cottage.
In an interview scheduled to air Friday on CNN's "Larry King Live," Linda Kasabian, a former Manson follower who was the prosecution's star witness against Manson and Atkins, recounted the Tate slayings. Watch Kasabian recall killings »
"I started hearing like horrible screaming and I started running toward the house and Sadie came running out and I just looked at her and I said, 'Sadie, please make it stop,'" Kasabian said. "And she said, 'I can't. It's too late.' ... It was unreal. It was so real that it was unreal."
On whether she asked Atkins and the others why they were killing, Kasabian said, "It wasn't that kind of a scenario. All that I said was, 'Sadie, make it stop.'"
For her safety, Kasabian asked to wear a disguise during the interview, which was conducted last month.
As of earlier this year, Atkins was paralyzed over 85 percent of her body and could not sit up in bed or be moved into a wheelchair, according to a Web site maintained by her husband and attorney, James Whitehouse. She has been described as a model prisoner who has accepted responsibility for her role in the slayings and now shuns Manson.
But Tate's sister, Debra Tate, told CNN in an e-mail in March that she does not think any Manson family member convicted of murder should ever be set free, saying the slayings were "so vicious, so inhumane, so depraved, that there is no turning back."
"The 'Manson Family' murderers are sociopaths, and from that, they can never be rehabilitated," Tate said. "They should all stay right where they are -- in prison -- until they die. There will never be true justice for my sister Sharon and the other victims of the 'Manson Family.' Keeping the murderers in prison is the least we, as a society who values justice, can do."
In a manuscript posted on her Web site, Atkins wrote that "this is the past I have to live with, and I have to live with it every day."
"Unlike the reader, or the people who seem to think Charles Manson was cool, I can't think about it for an hour or so and then go on with my life. Just like the families and friends of the victims, this is with me every day. I have to wake up every day with this and, no matter what I do for the rest of my life and no matter how much I give back to the community, I will never be able to replace what my crime took away. And that's not 'neat,' and that's not 'cool.'"
Atkins' brain cancer was diagnosed in March 2008, Whitehouse wrote on his Web site. On May 15, doctors predicted she would live less than six months. But she passed that deadline, he wrote, and celebrated her 21st wedding anniversary on December 7.