VACAVILLE, Sept. 25 — Mass killer Charles Manson was drenched with paint thinner and set afire today by a fellow inmate who told guards Manson had threatened him because of his religious beliefs, authorities said.

Manson, serving a life sentence for the cult slayings of actress Sharon Tate and eight others, was treated for second-and third-degree burns in the prison Infirmary and was in good condition, said Bob Gore, spokesman for the state Corrections Department.

Manson, 48, was in the hobby shop of the California Medical Facility, the state’s prison for psychiatric prisoners, when the other inmate, a member of the Hare Krishna sect serving a sentence for murder, doused him with flammable liquid and set him afire, Gore said. Manson suffered burns over 18 percent of his body, concentrated on his face, scalp and hands, in the 8:45 a.m. attack, Gore said.

The prison is located about 50 miles northeast of San Francisco.

Gore described the liquid as paint thinner, which is available in the hobby shop. Many inmates carry matches for cigarette smoking, he added.

The attacker was identified as Jan Holmstrom, 36, serving a life term for second-degree murder. He was also convicted during his prison term of assault with a deadly weapon and assault on a peace officer.

Gore said Holmstrom, termed “a psychiatric case in remission,” told officers Manson had threatened him for Holmstrom’s religious beliefs.

Manson, whose murders were described in the book “Helter Skelter” by former Los Angeles County prosecutor Vincent Bugliosi, has repeatedly been denied parole by the state Board of Prison Terms.

Manson, who led a tribe of young followers on a murder spree that shocked the world, was convicted with three women followers in the infamous Tate-LaBianca killings.

On the hot summer night of Aug. 9, 1969, the Manson clan invaded the Beverly Hills mansion of actress Sharon Tate, who was eight months pregnant, and stabbed her to death. They also murdered her house guests, Abigail Folger, Voityck Frykowski and Jay Sebring as well as a caretaker’s friend, Stephen Parent.

The following night, as news of the celebrity murders spread, the Manson followers killed two more strangers – wealthy grocery owners Leno and Rosemary LaBianca — who were found butchered in their Los Feliz area home.

Testimony at the Manson trial showed that the cult leader, a habitual criminal who had spent most of his life in prison, had ordered his disciples to murder at random. Although Manson himself did not kill any of the victims, he was found guilty along with Susan Atkins, Patricia Krenwinkel and Leslie Van Houten. Manson also was later convicted in the slayings of musician Gary Hinman and ranch hand Donald “Shorty” Shea.

The three Manson women are imprisoned at the California Institution for Women at Frontera and have also been denied parole.

Another Manson follower, Charles “Tex” Watson, the lieutenant who led the murderers to the Tate and LaBianca homes, also remains in custody at San Luis Obispo serving a life sentence.

Manson and the women were originally sentenced to die in the gas chamber but their sentences were commuted to life imprisonment when the death penalty was ruled unconstitutional by the U. S. Supreme Court.