Mobile communications are not trustful as many people think about it. The IMSI catcher device is one of the most effective threats that can compromise the security of mobile communications. It is a radio device that acts as a fake cellular base station allowing near mobiles to join it instead of legitimate base stations. It uses a type of attack called man in the middle (MITM). The IMSI catcher can do almost everything after being connected to its victims, such as eavesdropping calls, intercepting SMS messages, locating phone's location and so many. It is widely used by government agencies legally to track criminals and terrorists, but nowadays it could be used by unauthorized individuals and criminal organizations for different purposes. Several of countermeasures against this threat are proposed by many researchers but most of them are reliant on real base station features to expose fake base stations. Those features are limited and could be easily imitated by IMSI catcher device. This paper presents a new IMSI catcher detection method, which relies on location area features for detection that makes it unique as compared to most of the existing schemes.