Recent technological advances have increased the prevalence of wireless networks in our society. Users can easily access the Internet at home, work, school or even while travelling. The ease of accessibility and mobility makes wireless networks a viable target for attackers. Compromised wireless networks allow attackers to eavesdrop on sensitive data such as passwords and credit card information. Attack detection schemes must identify when an attack is taking place, then mitigate this threat. Good detection solutions must have a high detection rate and low false positives. In our work, we consider a general form of the evil twin attack, called the evil twin transmitter attack. In the evil twin transmitter attack, a malicious wireless node gains access to the network and uses the same identity as a legitimate wireless node. We aim to minimize this threat and localize the wireless nodes involved. Our contributions to this work are: 1. We describe two algorithms using four-square antennas at the receivers, which can be implemented in the most common deployment scenarios, such as a random or a regular grid networking environment, to detect an evil twin attack. 2. We propose two location estimation schemes that use the phase di