Telecom-fraud detection using device-location information

Subject matter described herein is directed to detecting unauthorized use, such as by a cloned mobile device, of wireless telecommunication services. Mobile-device locations are analyzed to detect outlying locations, such as locations that lack a call relationship with other locations or that are greater than a threshold distance away from other locations. Outlying locations might be detected when more than one discrete location cluster exists among a plurality of mobile-device locations, the discrete clusters having respective locations that are not related by way of a call and that fail to satisfy a threshold distance. Outlying locations or multiple discrete locations clusters suggest an unauthorized use of a mobile device's account.