Mississippi judge rules 'tower dump' warrants unconstitutional, blocking mass cellphone data sweeps

A federal judge in Mississippi has ruled that "tower dump" warrants, which let police obtain from carriers the records of every mobile device connected to specific cell towers during a set time frame, violate the Fourth Amendment of the U.S. Constitution. The decision upheld a lower court's refusal to grant such warrants in investigations of a string of violent crimes.

Law enforcement had sought these warrants last year as part of probes into gang-related activity in the Jackson area, arguing the data could help identify everyone involved in incidents, particularly where suspects were unknown. A magistrate judge rejected the applications, calling "tower dumps" impermissible general warrants, and the district court agreed.

In his 30-page order, Judge Carlton Reeves referenced the Supreme Court's recent ruling in Chatrie v. United States, in which a majority held that geofence warrants require constitutional privacy protections. Reeves noted that while the government claims it could identify all potential suspects, the warrant would also expose the records of countless individuals, most of whom merely happened to be near a location at the "wrong" time.

The judge concluded that this constitutes an unreasonable search under the Fourth Amendment. The ruling sets a precedent that curbs police authority to conduct indiscriminate sweeps of citizens' location data via cellphone providers.