Abstract: A method and apparatus for determining whether a door is closed and locked. A door lock system includes a bolt, transmitter circuitry, and receiver circuitry. The bolt includes a first end that is extendible to engage a strike plate. The first end includes an opening, and channel extends from the opening longitudinally through the bolt. The transmitter circuitry is coupled to the bolt, and is configured to transmit a signal into the channel. The receiver circuitry is coupled to the bolt, and is configured to detect a reflection of the signal returned through the channel.