"I’d go to the mall and see women and imagine them without faces"

He pulled up to the house and saw a lump of clothing in the driveway. “Then I realized it’s a human being,” he said. “It was all ripped apart.”

He parked to the right of the body, and the other officer parked on its left. Officer Chiafari’s car blocked the body from the front porch, where he saw Travis jumping up and down, in a “frenzy.”

“He starts bashing the passenger window,” he said. “I’m terrified. I see what he’s done to the victim.” He drew his pistol, but Ms. Herold, who had been hiding in a vehicle, emerged behind the chimp, entering his line of fire. He looked back at the victim. “She had no face, and there’s blood pulsating out. She’s bleeding out.” He holstered his gun…

There was blood all over the chimp, whose owner had stabbed him in the back with a butcher knife. The chimp seemed as surprised that he had opened the door as Officer Chiafari, who was pinned in his seat by a computer console and again drawing his pistol.

“He gave me a split second to react,” he said. “He shows his teeth, a snarl, and I see blood. I see his fangs. I just start to shoot.”