(CNN)Leslie Van Houten, a Charles Manson follower convicted in a 1969 killing spree, was denied parole for a fourth time in four years on Friday.
The California parole board in January recommended parole for Van Houten. California Gov. Gavin Newsom said in a parole release review obtained by CNN that he believes Van Houten "currently poses an unreasonable danger to society if released from prison at this time."
"Given the extreme nature of the crime in which she was involved, I do not believe she has sufficiently demonstrated that she has come to terms with the totality of the factors that led her to participate in the vicious Manson Family killings," Newsom wrote in his decision.
Newsom added that despite Van Houten's productive time in prison -- she earned a bachelor's and master's degrees and completed "extensive" self-help programming -- the negative factors of her involvement in the murders outweighed the positive factors.
Van Houten, 71, is serving a life sentence at the California Institute for Women in Corona after being convicted for a pair of 1969 murders and conspiracy to kill five others.
She was 19 years old when she met Charles Manson and became part of his murderous cult that came to be called the "Manson Family," according to parole documents.
On August 10, 1969, she and other members of the Manson Family brutally stabbed Leno and Rosemary LaBianca to death at their home in Los Angeles. Van Houten was arrested November 25, 1969.
Van Houten was sentenced to death in 1971, but one year later the death penalty was overturned. Her first conviction was overturned, too, because her lawyer died before that trial ended. She was tried twice more -- one ending in a hung jury -- and was sentenced to life in prison following a 1978 guilty verdict.
Newsom said he understood Van Houten was 19 at the time of the crime and that a psychologist who evaluated her said it was likely her involvement in the killings were "significantly impacted" by youth factors, such as her impulsivity and the inability to manage her emotions
"Before she can be safely released, Ms. Van Houten must do more to develop her understanding of the factors that caused her to seek acceptance from such a negative, violent influence, and perpetrate extreme acts of wanton violence," Newsom said.
This is her 23rd appeal and the fourth time the board has deemed Van Houten suitable for release. Her three previous approvals for release were blocked twice by former Gov. Jerry Brown and once by Newsom.
Since 2016, Manson family members Charles Watson, Patricia Krenwinkel, Bobby Beausoleil and Bruce Davis have been denied bids for parole.
Manson died of natural causes in 2017. He was 83.