They recommended that Davis be paroled in the 1969 slayings of musician Gary Hinman and stuntman Donald “Shorty” Shea.
It is the fourth time for such a recommendation, but 72-year-old Davis remains imprisoned at the Men’s Colony in San Luis Obispo.
The previous three such recommendations by the Board of Parole Hearings were blocked, once by former governor Arnold Schwarzenegger and twice by governor Jerry Brown.
Mr Brown most recently rejected Davis’ parole a year ago, saying he remains dangerous despite his age. It will be about five months before Mr Brown decides on Thursday’s recommendation.
“I am pleased the board again followed the law and did the right thing, and I am hopeful that the governor will do likewise,” Davis’s lawyer, Michael Beckman, said after the hearing.
Davis was not involved in the killings of actress Sharon Tate and six others, but LA County deputy DA John Morris said the lesser-known slayings are reason to keep him behind bars.
“The heinousness of the crimes held California in the grip of fear for months,” said Mr Morris, who heads the district attorney’sdivision and drove to San Luis Obispo to oppose Davis’s parole.“