A locking system and method for a movable freight container comprises an electronic module with a shaft that goes into a cavity in a mechanical lock module. The shaft is securely retained in the cavity by a lock mechanism in the mechanical lock module by moving the lock mechanism to a locked position. A plurality of magnetic field sensors in the shaft are used to read the position of the shaft in the cavity by sensing or not sensing one or more magnets in the lock mechanism to confirm continuous time insertion of the shaft in the cavity. A wireless communication component in the electronic module wirelessly transmits an alarm signal if the magnetic field sensors detect an unexpected interruption in at least one of the continuous time shaft position magnetic sensor readings.