Detecting the cheating or vulnerable beacon node is an essential problem in wireless sensor networks. In wireless sensor networks, beacon nodes are used to locate or trace the exact location of the object. Now-a-days it is challenging to find out the exact location of a beacon node from the existence of a cheating beacon node. Even after finding out the location of cheating beacon node, there are chances of errors that can likely happen. This paper localizes the cheating beacon nodes using trilateration algorithm and later compare it with Maximum Likelihood Expectation method to obtain maximum accuracy in localization.