I once made a secure closet in my house to protect instruments when I wasn't at home. Put a deadbolt on the door, and on the hinge side took out the middle screw from one half of each hinge and unscrewed the opposite middle screw part way and hacksawed the head off. Then when the door was shut the sawn screw fit into the empty hole where the other screw had been and if anyone tried to remove the door by removing the hinge pivot bolts, the door wouldn't move.