Abstract: Provided is an apparatus for use for a pivotally mounted door disposed in a wall and usually mounted within a door frame. Pivotal mounting of the door is on a hinge. The security apparatus is mounted to a door frame or wall above the door by any suitable technique and is comprised principally of two main body portions in the form of a fixed clamshell and a pivoting clamshell connected by a piano hinge. These clamshell portions enclose a few operative portions of the structure including a locking mechanism preferably comprised of a pivoting key operated lock, a pivoting lock dog, a lock dog lip and a door strike plate. The fixed clamshell is attached to the wall or door frame top by apparatus that may include large size screws or bolts, or the device may be welded thereto as desired. The attaching means is contained within the clamshell enclosure to prevent tampering therewith. The clamshell portions are formed of plates and ends to totally enclose at all times operative portions of the apparatus.