The jury in the murder trial of Royal Kenneth Hayes left a Santa Cruz courtroom to tour the spot where witnesses have said they helped Hayes shoot, mutilate and bury two people after he lured them there with a promise of cocaine. The panel of eight women and four men, along with the judge and attorneys, stood in a shallow depression near the University of California, Santa Cruz, campus, where Hayes is said to have killed his former girlfriend, Lauren deLaet, and her companion, Donald MacVicar. Witnesses--including two other former girlfriends of Hayes who said they helped him with the killings--have testified that Hayes used a pistol and a silencer, chopped off the victims' hands and heads to deter identification and buried the torsos in a shallow grave. One of the women went to police after a skull was found in March, 1982. She testified that Hayes lured the pair to the site by telling them they would meet a man who would give them $250,000 worth of cocaine.