LOS ANGELES, May 27 – Robert K. Beausoleil, condemned to death for one of eight sayings police have attributed to the “Manson Family,” has been granted permission to act as his own attorney in seeking a new trial.

Beausoleil’s request was granted Tuesday after the 22-year-old defendant presented an affidavit claiming a key prosecution witness lied in testimony about the stabbing death of bagpipe musician Gary Hinman.

Charles Manson, 35, accused mastermind of the Hinman slaying and the seven Tate – Labianca killings, also has been charged in the case along with another family member, Susan Atkins.

Manson and Miss Atkins were scheduled to appear in court today for pre-trial arguments in the Tate-Labianca case.

Superior Court Judge William B. Keene put off formal sentencing for Beausoleil and gave him until June 9 to bring in new evidence the defendant hopes will clear him.

Beausoleil claimed public defender Leon Salter was unable to obtain the evidence because members of the hippie cult and other witnesses distrust the lawyer and other members of “the establishment.”

He presented what he said was an affidavit from Mary Brunner, a key prosecution witness, in which she claimed her testimony that Beausoleil stabbed Hinman to death was false, and that police had ”coerced” her to testify by threatening to take away her small child.

“She’d say anything to keep her baby,” Beausoleil told Keene. The defendant said he would obtain evidence indicating it was “impossible” for him to have killed Hinman and that prosecution witnesses were “coerced” to say he did.

Keene gave Beausoleil permission to act as his own attorney “for the limited purpose” of gaining evidence to back up his request for a new trial. He warned Beausoleil his claims had better not be “delaying tactics.”

“My life is at stake,” Beausoleil replied. “I’m not playing games.”

Deputy District Attorney Burton Katz said he had learned of Miss Brunner’s affidavit only shortly before it was presented in court and that he had not checked its authenticity. He said, however, he believed there was other evidence presented at the trial sufficient to convict Beausoleil.