A high security locking system can be used in a conventional pivot door adapted for use with a latch and deadbolt lock combination. The high security system can be a multi-point lock, received in a recess formed in a locking edge side of a door stile, cooperating with a linkage or other mechanism in a conventional deadbolt/location. The lock can be actuated with a keyed cylinder and thumb turn combination.

A latch having a support bracket having a guide slot formed in a bottom surface. A linkage at least partially received within the guide slot and a handle coupled to the linkage transitionable between an open position and a closed position. A pin releasably coupled to the linkage such that when the handle is in the closed position the pin is coupled to the linkage and in the open position the pin is removable from the linkage. As the handle transitions from the open position to the closed position, the linkage moves within the guide slot.