Abstract: Security lock assembly includes a movable lock bolt adapted for mounting to a door, and a striker unit adapted for mounting to a door jamb, which unit defines a bolt cavity. Latch means is mounted for movement to an operative position protruding into the cavity in which the latch means is engagable with the bolt to prevent its withdrawal from the cavity. Drive means drives the latch means to its operative position. A magnetized element in the bolt causes a magnetically operable switch mounted on the striker unit adjacent the bolt cavity to activate the drive means on the receipt of the lock bolt in the cavity.