The California Court of Appeal has held that a geofence warrant seeking information on all devices located within several densely-populated areas in Los Angeles violated the Fourth Amendment. This is the first time an appellate court in the United States has reviewed a geofence warrant. The case is People v. Meza, and EFF filed an amicus brief and jointly argued the case before the court.
Geofence warrants, which we have written aboutextensively before, are unlike typical warrants for electronic information because they don’t name a suspect and are not even targeted to specific individuals or accounts. Instead, they require a provider—almost always Google—to search its entire reserve of user location data to identify allusers or devices located in a geographic area during a time period specified by law enforcement.
In the Meza case, Los Angeles Sheriff’s Department deputies were investigating a homicide and had video footage suggesting the suspects followed the victim from one location to another before committing the crime. To try to identify the unknown suspects, they sought a warrant that would force Google to turn over identifying information for every device with a Google account that was within any of six locations over a five hour window. The warrant covered time periods where people were likely to be in sensitive places, like their homes, or driving along busy streets. In total, police requested data for geographic area equivalent to about 24 football fields (five to six city blocks), which included large apartment buildings, churches, barber shops, nail salons, medical centers, restaurants, a public library, and a union headquarters.