BOISE, Idaho (AP) — A break-in at Zoo Boise early Saturday left a Patas monkey dead from blunt force trauma to the head and neck and police were analyzing blood found at the scene to determine if it came from the monkey or one of two human intruders.

Two males wearing dark clothing were spotted by a security guard at 4:30 a.m. outside the fence near the primate exhibit, police said. Both fled, one of them heading into the interior of the zoo. Boise police used a thermal imager in searching the 11-acre zoo grounds but didn’t find the person.