LOS ANGELES, Apr. 20 – The prosecution will seek the death penalty Monday for Robert Beausoleil, the 22-year-old “Manson Family” member convicted of the 1969 torture slaying of bagpipe musician Gary Hinman.

Beausoleil, his parents looking on, slumped in his chair and covered his face with his right hand Saturday when the verdict of the seven-woman, five-man jury was read.

Mr. and Mrs. Charles Beausoleil, of Santa Barbara, Calif., appeared shaken by the verdict. Their 14-year-old son, Stephen, wept.

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

The prosecution presented witnesses who testified that Beausoleil stabbed Hinman to death July 27 after torturing him for 48 hours to force him to turnover $20,000 he was believed to possess.

The witnesses also said that Charles Manson, alleged mastermind of the Sharon Tate slayings the following month, ordered Beausoleil to kill Hinman.

Taking the stand on his own behalf, the defendant said that Manson actually did the killing.

The hippie cult leader and two of his followers were indicated last week for the Hinman murder.