LOS ANGELES, May 28 – Susan Atkins changed her plea in the Hinman – Shea murder case Thursday and pleaded guilty to killing musician Gary Alan Hinman in Topanga Canyon nearly two years ago.

The slender, pale young woman, her head shaved, a faint “X” of the Charles Manson “family” scarring her forehead, waived all rights and listened without emotion as the judge sentenced her to life in prison. She already is under a death sentence in the Tate-LaBianca slayings.

“The court believes, from having read the record in this case of the grand jury indictment,” said Superior Judge Raymond Choate, “that she is a person who would be dangerous to the community.

“And the court believes that, for the guidance of the Adult Authority, that she should spend the entire term of her life in custody.”

For 22-year-old “Sexy Sadie,” Choate’s words may only be academic. He ordered her taken to California Institution for Women at Frontera in Riverside County.

There she will join Patricia Krenwinkel, 23, and Leslie Van Houten, 21, in a special security area prepared after the three and Charles Manson were condemned to death for the Tate-LaBiana murders.

After Choate pronounced sentence with “Sadie” standing beside her attorney, Daye Shinn, she turned and seemed to nod at the 36-year-old Manson sitting to her left at the counsel table.

He showed no sign of recognition.

As Miss Atkins walked behind Manson’s swivel chair, she lightly pulled her right hand acosss his back. Manson didn’t appear to notice, nor did he look at her as she walked from the courtroom.

Her exit left Manson, Bruce Davis, 27, and Steve Grogan as the remaining defendants in the killing of Hinman and the reported murder of ranch hand Donald (Shorty) Shea, 38.

Shea disappeared from Spahn ranch, a Manson family hangout in Chatsworth, in August, 1969. The prosecution claims he was murdered, but his body has never been found.

Manson and Davis are charged with helping to murder both Hinman and Shea. Grogan is accused of decapitating Shea.

Miss Atkins changed her plea after her attorney met with Dist. Atty. Joseph P. Busch Jr. and co-prosecutors Burt Katz and Anthony Manzella. Jr.

The arrangement was that the district attorney’s office would recommend a life sentence for Miss Atkins if she pleaded guilty, nothing else.

She will not testify against the other defendants during the trial.

Katz explained to Choate that his office had two reasons for the action. First, he said, he thinks the evidence will show she did not wield the knife which killed Hinman, and, second, she already has been convicted of murder and condemned to death.

Miss Atkins waived her rights to a jury trial, to a court trial, to self-incrimination and cross-examination of prosecution witnesses and admitted she was present in Hinman’s Malibu house when he was killed in late July, 1969.

“Did you participate in the killing of Gary Alan Hinman?” Katz asked.

“Yes,” she replied.

“Did you do so with knowledge that your acts would result in the death of Gary Alan Hinman?”

“Yes.”

She admitted she helped smother Hinman with a pillow and wiped down the house for fingerprints, but she balked at saying she knew that the object at Hinman’s home was robbery.

By JOHN KENDALL