LOS ANGELES, Apr. 21 – Following daylong arguments, a Los Angeles Superior Court jury Monday began deliberating whether Robert Beausoleil, convicted of first-degree murder Saturday in the death of musician Gary Hinman, will face death in the gas chamber or life in prison.

The baby-faced Beausoleil sat stoically throughout the lengthy arguments, including the introduction of four letters written by him — one to a member of the Manson family, and the other three in his parents.

Demanding the death penalty, Deputy District Atty. Burton Katz called the killing of the 34-year-old musician in his Topanga Canyon home July 27, “vicious, brutal, remorseless, senseless and callous disregard for human life.”

Katz introduced a letter into evidence which indicated Beausoleil would “be wearing a common face in the courtroom and for that reason I sent a note to the family not to write or visit me while I’m here in jail.”

The letter, addressed to Ouis (the “family” nickname for Ruth Ann Moorehouse) indicated the district attorney would try to use the fact that Beausoleil had been in touch with the family. Beausoleil testified at his trial that he was not a family member but only a friend of Charles Manson, leader of the hippie cult.

Beausoleil contended Manson killed Hinman. Defense attorney Leon Salter introduced three letters from Beausoleil to his actual family, who live in Santa Barbara. His father, Charles, took the stand in his son’s defense reading from the letters:

“I’ve learned wisdom from both fools and wise men,” Beausoleil wrote. “I’ve learned that only fools follow leaders, and to follow a leader is to be led by the blind.”

The prosecution contended during they trial that Beausoleil killed Hinman at the orders of his leader, Manson.

After deliberating on the penalty 45 minutes Monday afternoon, the jury was locked up for the night. The five-man, seven-women jury is expected to reach a penalty verdict today.

Meanwhile, as Beausoleil awaited his fate in one court, another member of the Manson family made an appearance in another courtroom.

Linda Kasabian, charged with Manson and four other family members of the Tate-LaBianca murders, appeared with her attorney to have her trial, setting date delayed until June 15.

The new date the same set for the trial of the other defendants, confirmed reports that the girl will not be tried with the other family members. She was reported to have been given immunity to testify for the prosecution.

By MARY NEISWENDER