Leslie Van Houten, the youngest of the Manson Family murderers, is the first to be been granted parole by a California board.
Van Houten, who was 19 when she killed for Manson during a series of murders that terrorised Los Angeles over the summer of 1969, appeared before a parole panel for the 21st time on Wednesday.
The decision now goes through a process of review in which Governor Jerry Brown may uphold, reverse or modify the decision.
He could also send the matter to the full Board of Parole Hearings, or take no action, in which case the parole decision would stand.
A similar panel at the California Institution for Women in Chino, where Van Houten, 68, is incarcerated, granted her parole last year but was overruled by the governor.
Van Houten has candidly described how she joined several other members of the “Manson Family” in killing Los Angeles grocer Leno La Bianca and his wife, Rosemary, in their home on August 9, 1969.
She was not with Manson followers the night before when they killed pregnant actress Sharon Tate – the then-wife of famous film director Roman Polanski – and four others during a similar bloody rampage.
Manson’s followers in all committed nine murders at four locations in July and August 1969, becoming arguably the United States’ most notorious serial killers.
At her parole hearing last year, Van Houten said she helped hold down Rosemary La Bianca while another Manson follower stabbed her repeatedly. She then took up a knife herself and added more than a dozen stab wounds.
“I don’t let myself off the hook. I don’t find parts in any of this that makes me feel the slightest bit good about myself,” she said.
Van Houten had been a high school homecoming princess, athlete and cheerleader before dropping out of school and joining the group who considered Manson, – a career con man and petty criminal – to be a Christ-like figure.
She has testified that the trauma of her parents’ divorce, her teen pregnancy and other problems led her to drop out of school, run away from home, become involved in drugs and eventually join Manson’s cult.
Since she was incarcerated more than 40 years ago, Van Houten has been a model prisoner and earned college degrees.
Members of the Tate and La Bianca families have repeatedly argued against granting parole to her or any other Manson follower who took part in the killings.
None has been freed, and one, Susan Atkins, died in prison in 2009.
Manson, now aged 82, is serving nine life sentences at Corcoran State Prison in Central California.
He was denied parole for the 12th time in 2012 and is not eligible again until 2027.
His original death sentence was commuted to life in 1977.