Home › Case briefs › Criminal Procedure

Carpenter v. United States

Supreme Court of the United States · 2018 · Criminal Procedure

Criminal ProcedureFourth Amendmentcell-site location datathird party doctrinedigital privacyCSLIhistorical cell-site recordssearch

Facts

After a series of robberies, the FBI obtained court orders under the Stored Communications Act requiring Carpenter's wireless carriers to disclose historical CSLI for his phone. MetroPCS produced 127 days of records and Sprint produced additional roaming records, yielding 12,898 location points that the Government used to place Carpenter's phone near several robberies. Carpenter argued the records were obtained without a warrant supported by probable cause and should be suppressed. The lower courts rejected that argument on the ground that he had shared the information with his carriers.

Issue

Does the Government conduct a search under the Fourth Amendment when it obtains historical cell-site location information from a wireless carrier, and if so, must it generally obtain a warrant supported by probable cause before doing so?

Rule

An individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through historical CSLI. Accordingly, the Government's acquisition of at least seven days of historical CSLI from a wireless carrier is a Fourth Amendment search, and the Government generally must obtain a warrant supported by probable cause before compelling disclosure of such records, subject to case-specific exceptions such as exigent circumstances.

🔒

See the holding & full analysis

Create a free KwikCourt account to unlock the rest of this brief — and practice the case.

The court's holding and reasoning
Doctrine tests, pitfalls & exam hypotheticals
10 practice questions + 4 AI-graded essays on this case

Free sample · practice this case

Test yourself

One of 10 multiple-choice questions for this case. Pick an answer to see why.

Detectives in Phoenix are investigating a string of pharmacy burglaries. Without seeking a warrant, they obtain a court order requiring Desert Star Wireless to disclose 14 days of Nadia Ruiz’s historical cell-site location information, based only on a showing that the records are relevant to the investigation.

Did the government conduct a Fourth Amendment search when it obtained Nadia’s records?

Explanation. The majority held that a person has a legitimate expectation of privacy in the record of her physical movements as captured through historical CSLI. Accessing at least seven days of historical CSLI is a Fourth Amendment search. The fact that the records are held by a carrier does not by itself defeat protection, and a mere relevance-based order falls short of the warrant supported by probable cause generally required.