a wire loop for conducting a current to establish an electrical circuit, wherein the wire loop comprises a common, non-heat-or-weather-resistant coaxial cable having a looped end, for use with parked vehicles, not to be operated at normal driving temperatures;

at least one hose clamp for securing at least a portion of the wire loop alongside and adjacent to a vehicle exhaust system including the catalytic converter, wherein the at least one hose clamp is looped around a tubular circumference of the vehicle exhaust system with the wire loop sandwiched between the at least one hose clamp and the catalytic converter;

a monitoring circuit, in electrical communication with the wire loop, for monitoring the electrical circuit established in the wire loop;

a detector circuit, connected to the monitoring circuit, for detecting a discontinuity in the electrical circuit indicative of a disconnection of the wire loop;

an alarm circuit, connected to the detector circuit, for activating an alarm upon detection of the discontinuity in the electrical circuit; and

a key-activated arming circuit comprising a key detection circuit for detecting a key insertion signal indicative of insertion of a removable key, and a wire loop detection circuit for detecting a wire loop insertion signal indicative of insertion of the wire loop corresponding to establishment of the electrical circuit.