Abstract: A high security door lock having a crossbar mounted on a door and a keeper mounted on the door frame. A pin with at least one projection is provided to secure the crossbar to the keeper by inserting the pin through at least one slot in the keeper. A locking channel is provided integral with the keeper and located at an angle to the slot in the keeper. When the pin is inserted into the keeper and rotated, the pin projection seats in the locking channel. A biasing means is provided to coact with the pin to hold the projection in the locking channel and prevent uncoupling of the crossbar from the keeper absent depression and rotation of the pin.