On April 22, 1974 Pierre, Andrews, Roberts and three other men drove to a Hi-Fi store on Washington Boulevard, Ogden, in two vans just before closing time. Three of the group then entered the shop brandishing handguns, while Roberts and another man remained with the vehicles.
Two employees, Stanley Walker, age 20, and Michelle Ansley, age 18, were in the store at the time and taken hostage. Pierre and Andrews took the two into the store's basement and bound them. The gang then began robbing the store. Later, a 16-year-old boy named Cortney Naisbitt arrived to thank Walker for allowing him to park his car in the store's parking lot as he ran an errand next door. He was also taken hostage and tied up in the basement with Walker and Ansley. Later that evening, Orren Walker, Stanley's 43-year-old father, became worried that his son had not returned home. Cortney Naisbitt's mother Carol Naisbitt, also arrived at the shop looking for her son, who was late getting home. Both Orren Walker and Carol Naisbitt were taken to the basement and tied up.
With five people now in the basement, Pierre told Andrews to get something from out of their van. Andrews returned with a bottle in a brown paper bag, from which Pierre poured a cup of blue liquid. Pierre ordered Orren to administer the liquid to the other hostages, but he refused, and was bound, gagged and left face-down on the basement floor.
Pierre and Andrews then propped each of the victims into sitting positions and forced them to drink the liquid, telling them it was vodka laced with sleeping pills. Rather, it was liquid Drano. The moment it touched the hostages' lips, enormous blisters rose, and it began to burn their tongues and throats and peel away the flesh around their mouths. Ansley, still begging for her life, was forced to drink the drain cleaner too, although she was reported (by Orren Walker) to have coughed less than the other victims. Pierre and Andrews tried to duct-tape the hostages' mouths shut to hold quantities of drain cleaner in and to silence their screams, but pus oozing from the blisters prevented the adhesive from sticking. Orren Walker was the last to be given the drain cleaner, but seeing what was happening to the other hostages, he allowed it to pour out of his mouth and then faked the convulsions and screams of his son and fellow hostages.
Pierre became angry because the deaths were taking too long and were too loud and messy, so he shot both Carol and Cortney Naisbitt in the backs of their heads, proving fatal for Carol however leaving Cortney alive. Pierre then shot at Orren Walker but missed. He then fatally shot Stanley before again shooting at Orren, this time grazing the back of his head.
Pierre then took Ansley to the far corner of the basement, forced her at gunpoint to remove her clothes, then repeatedly and brutally raped her, after telling Andrews to clear out for 30 minutes. When he was done, he allowed her to use the bathroom while he watched, then dragged her, still naked, back to the other hostages, threw her on her face, and fatally shot her in the back of the head.
Andrews and Pierre noted that Orren was still alive, so Pierre mounted him, wrapped a wire around his throat, and tried to strangle him. When this failed, Pierre and Andrews inserted a ballpoint pen into Orren's ear, and Pierre stomped it until it punctured his eardrum, broke, and exited the side of his throat. Pierre and Andrews then went upstairs, finished loading equipment into their van, and departed.