LOS ANGELES, California (CNN) -- The woman who stabbed pregnant actress Sharon Tate to death will be considered for parole from prison a month after the 40th anniversary of the killings that cast a shadow of fear over southern California.

Susan Atkins, shown here after her indictment in the Manson murders, has been denied parole 17 times.

Susan Atkins, 61, has been denied parole in 12 previous hearings, but the former "Manson Family" member now is terminally ill with brain cancer and is paralyzed.

Charles Manson used his hypnotic powers to direct Atkins and other "family" members to kill seven people, including the pregnant Tate, in a two-night rampage that terrorized the city of Los Angeles, California, in August 1969.

Atkins -- who was initially sentenced to death along with Manson and three others -- will have her 13th parole hearing on September 2, according to a spokesman with the California Department of Corrections and Rehabilitation.

In July of last year, Atkins -- California's longest-serving female inmate -- was denied a compassionate release in a unanimous decision by the California Board of Parole Hearings.

She has repeatedly been described as a model prisoner who has accepted responsibility for her role in the slayings, and she now shuns Manson.

By her own admission, Atkins held Tate down as she pleaded for mercy and stabbed the pregnant woman 16 times. 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 stabbing Tate to death, according to historical accounts of the murders, 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 at the time, 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.

A Web site maintained by her husband and attorney, James Whitehouse, says Atkins is now paralyzed over 85 percent of her body and cannot sit up in bed or even be moved into a wheelchair.

However, despite her declining condition and her impressive prison record, the site says, "there is still a very real chance the Parole Board will nonetheless insist her release would be a danger to society."

Atkins' compassionate release was opposed by Tate's sister, Debra, Los Angeles County prosecutors and California Gov. Arnold Schwarzenegger, among others. However, the former prosecutor who won her conviction, Vincent Bugliosi, said he supports Atkins' request for release.

"She has paid substantially, though not completely, for her horrendous crimes," Bugliosi told the Los Angeles Times last year. "Paying completely would mean imposing the death penalty."

Bugliosi is the author of several books on the Manson case, including "Helter Skelter."

Debra Tate told CNN in an e-mail in March that she does not believe 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," Debra 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, who was known within the Manson family as Sadie Mae Glutz, 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 was housed in the California Institution for Women at Frontera until May 2008, when her declining health caused her to be moved to Central California Women's Facility at Chowchilla.

Manson and those convicted along with him in the murders -- Atkins, Patricia Krenwinkel, Leslie Van Houten and Charles "Tex" Watson -- have been in California prisons for more than three decades.

All were initially sentenced to death, only to have their sentences commuted to life in prison when the Supreme Court struck down death penalty laws in 1972, establishing a four-year moratorium on executions. Van Houten was released for six months after her conviction was overturned, but was reconvicted.

CNN's Ashley Broughton contributed to this report

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