Geofence warrants, also known as reverse location searches, are a relatively new investigative technique used by law enforcement to try to identify a suspect. Unlike ordinary warrants for electronic records that identify the suspect in advance of the search, geofence warrants essentially work backwards by scooping up the location data from every device that happened to be in a geographic area during a specific period of time in the past. The warrants therefore allow the government to examine the data from individuals wholly unconnected to any criminal activity and use their own discretion to try to pinpoint devices that might be connected to the crime.