Methods and systems are described for the detection and identification of a cellular device that crosses a perimeter associated with a premises that is installed with a monitoring system. Subsequently, a determination of an intruder crossing the perimeter and/or entering a building within the premises may be made based on receiving unique identification values for the cellular device and/or information associated with a user of the cellular device. One or more sensors present within or near the premises may be configured to send alert information when tripped. The monitoring system may be configured to determine a location of the cellular device, an identity of the user of the cellular device, additional information stored, transmitted or received by the cellular device, and safe escape routes that may be sent to one or more user devices registered with the monitoring system.