Abstract: A device for detecting tampering with standard mechanical locksets has a pair of electrical contacts placed within the recess that receive lock's bolt and a third conductor positioned to run vertically along the door frame. A control box sends a low-level radio frequency (RF) signal to the first contact that in turn energizes the entire lockset when the bolt is in its extended position. The second contact returns RF energy to the control box to signal that the bolt is in its extended or locked position. Measured changes in capacitance serve to automatically enable tamper detection when the lockset is in its locked position; further, to automatically signal an alarm when the locked lockset is tampered with, to automatically disable tamper detection when the lockset is in its unlocked position and to define one or more protected areas whose status may then be signaled through conventional multi-zone security systems.