A 14-year-old girl murdered a well-known animal rescuer, bludgeoning him to death for unknown reasons inside the Northeast Philadelphia apartment where he cared for his 11 cats, officials said Saturday.

The body of Albert Chernoff was found at 3 a.m. Tuesday, partially bound to a bed with a massive head wound and slashing injuries to his chest, The Philadelphia Inquirer reported.

The suspect, arrested Thursday, had been seen on the victim’s home security cams calmly puttering around the kitchen.