Summary
In Carpenter v. United States, the Supreme Court held that law enforcement's acquisition of extensive historical cell-site location information is a Fourth Amendment search. A lower Stored Communications Act order was not enough; a probable-cause warrant is generally required for this kind of detailed location tracking.
Legal Issue
Does the government's acquisition of historical cell-site location information from a wireless carrier constitute a Fourth Amendment search requiring a warrant supported by probable cause?
Holding
Yes. The Supreme Court held that acquiring Carpenter's historical cell-site records was a Fourth Amendment search. In general, police must get a warrant supported by probable cause before obtaining such extensive CSLI, though the Court left room for exceptions like exigent circumstances.
Rule of Law
Police usually need a warrant before getting a person's long-term cell phone location history from a carrier.
Court Reasoning
Not yet summarized.
Impact for Officers
Carpenter remains a central digital privacy case for law enforcement requests involving historical location records, geofence data, app location histories, and other surveillance tools that can reconstruct a person's movements over time.
What Officers Can Do
Not yet summarized.
What Officers Should Avoid
Not yet summarized.
Common Misunderstanding
Not yet summarized.