The Los Angeles County district attorney is trying to stop the release of former Charles Manson follower Bruce Davis, who was convicted of participating in two killings.
District Attorney Steve Cooley wrote to Governor Arnold Schwarzenegger on Friday, saying he believes the 67-year-old Davis remains a danger to the public.
Davis' lawyer Michael Beckman said his client is completely rehabilitated and meets state requirements for parole.
Cooley is asking the governor to reverse a parole board decision on Davis.
Davis has been in prison since 1972 after being convicted in the murders of musician Gary Hinman and stuntman Donald "Shorty" Shea.
Davis was not involved in the Manson family's infamous murders of actress Sharon Tate and six others in 1969.