Electrical power theft is the main cause of Non Technical Losses (NTL) in the electrical power system. This paper is intended to provide with an innovative scheme for the detection and monitoring of Electrical power theft in the Electricity distribution system based on the principle of Power line Communication. A Narrow band power line carrier signal is injected into the distribution power line along with the power frequency signal (230V, 50Hz). Any illegal utilization of electricity will be detected with the differential change in the amplitude of the narrow band carrier signal which can be detected with precision. Simulation results using MATLAB software are provided showing that the scheme is simple and efficient.