In Virginia, police used a technique called geofencing to query Google’s records to identify people who had been near a Midlothian bank when a robber brandished a gun and fled with $195,000. Instead of seeking permission to search a particular home or person, investigators drew a virtual perimeter around the crime scene and asked a tech company to comb its location data for any users who were inside that zone at the time.
Geofencing lets authorities define a geographic area and obtain data about devices that were there. Prosecutors obtain warrants not to search a single suspect’s property, but to compel companies to search vast databases for any users who crossed the virtual line. Critics say the practice can sweep up innocent people’s movements and reveal sensitive information about where they go and whom they meet.
The technique is now before the U.S. Supreme Court under the Fourth Amendment, which protects against unreasonable searches and requires warrants issued by neutral magistrates and targeted at specific evidence of wrongdoing. The Court must decide whether geofencing investigations are a lawful, modern investigative tool or an intrusive, surveillance-style search that violates constitutional privacy protections — in short, whether the method is ingenious, Orwellian, or both, and whether it can be used consistent with the Constitution.