LOS ANGELES, Apr. 19 – Robert K. Beausoleil, reportedly a one-time member of the Charles Manson “family,” was convicted of first-degree murder Saturday in the torture death of musician Gary Hinman.

A seven-woman, five-man Superior Court jury deliberated two days before returning the verdict against the 22-year-old defendant, who had testified it was Manson who stabbed Hinman to death last July 27.

Manson, the alleged mastermind in the Tate-LaBianca murders, and two of his hippie cult members were indicted earlier in the week in the Hinman murder.

The prosecution said it will press for the death penalty in the penalty phase of Beausoleil’s trial, which is scheduled to begin Monday.

The pale, slightly built Beausoleil slumped briefly in his chair, his right hand covering his face, after the verdict was read Saturday.

But he sat upright and listened attentively as jurors were polled by Superior Judge William B. Keene, in whose court Beausoleil’s second trial for the murder began on March 30. The first trial ended in a hung jury last December.

Sitting behind Beausoleil in the first row of the courtroom Saturday was his father, Charles Beausoleil, a Santa Barbara route foreman for a milk company. The elder Beausoleil placed his arm around his wife and appeared to be fighting back tears. The couple’s youngest son, Stephen, 14, cried quietly.

“Our son is innocent,” Mrs. Beausoleil said afterward, “God knows he is innocent.”

She first said she was not surprised by the verdict, then said, “Yes, I am surprised because Bobby is completely innocent.

“I will tell you how I feel. God has given us strength this far and I will continue to depend on Him.”

The young defendant, wearing a green blazer and green trousers with high top shoes, entered the courtroom shortly before 2 p.m. Saturday. He smiled at his family and gestured toward them with his fingers crossed.

Apparently nervous, he smoked a cigaret, chatted with his attorney, Dep. Public Defender Leon M. Salter, and frequently turned around to glance at his family before the judge and jurors entered.

After the verdict was read he looked solemn as Judge Keene instructed jurors to reconvene Monday at 10 a.m. to start the penalty phase of the trial.

Dep. Dist. Atty. Burton Katz, who has said throughout the trial he will seek the death penalty, said Saturday the verdict “restored my faith in the jury system.”

He said he had been “concerned whether the jury would be influenced by extraneous factors such as the good looks and youthful appearance of the defendant.”

He said he did not think grand jury indictments linking others with the Hinman murder played a major role in the verdict, adding that “if anything, the contrasts in their physical appearance (Manson and Beausoleil) helped the defendants case.”

Aside from the link with the Tate and LaBianca murder cases, Beausoleil’s retrial commanded much public attention because testimony brought out two versions of the Hinman slaying.

Two witnesses for the prosecution, Mary Brunner, 26, and Danny DeCarlo, 25, testified that Beausoleil killed Hinman, 34, on orders from Manson.

Miss Brunner, a former University of Wisconsin librarian and mother of a child fathered by Manson, testified that she, the defendant and another Manson family member, Susan Atkins went to the Hinman home July 25 to try to get $20,000 from the musician.

She said that 48 hours later she saw Beausoleil kill Hinman with stab wounds in the chest when the musician refused to cooperate.

Miss Atkins previously had been charged in the Hinman murder in a complaint filed before she, Manson and other family members were accused of the Tate-LaBianca murders.

She, Manson and Bruce Davis, 27, were indicted last Tuesday in the Hinman slaying on testimony believed to have been given the grand jury by Miss Brunner who has been given immunity in the case. The earlier complaint against Miss Atkins was dropped. Davis has not been arrested.

Beausoleil, testifying in his own defense, accused Manson of actually killing Hinman.

Defense attorney Salter said Saturday the jury “believed Mary Brunner and they didn’t believe my client.” He maintained that Miss Brunner was protecting Manson because she was in love with him.

He said he attributed the difference in outcome in Beausoleil’s two trials to two things: “Publicity, which, since December, has created an entirely different situation between this trial and the first trial, and the fact that there was the extra witness in this trial — an eyewitness.”

Salter said the conviction will be appealed but that another attorney will handle it since his function in the public defenders office was limited to the first phase of the trial.

Beausoleil is the oldest of five children, his mother said Saturday.

By DOROTHY TOWNSEND