BOISE, Idaho – Police said they're following leads in the search for two intruders believed to have killed a monkey at Zoo Boise.

Boise police spokeswoman Lynn Hightower said detectives want to protect the investigation and aren't revealing whether they think the zoo break-in early Saturday morning was a prank that turned violent or something done with more sinister intent. She says police have heard from plenty of residents who are angry about the crime.

The patas monkey was found outside its exhibit near the perimeter fence, shortly after a security guard scared off two intruders. The monkey had a blunt force head injury and died a short time later.