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Carpenter v. United States - 138 S. Ct. 2206 (2018)


Given the unique nature of cell phone location records, the fact that the information is held by a third party does not by itself overcome the user’s claim to Fourth Amendment protection. Whether the government employs its own surveillance technology or leverages the technology of a wireless carrier, an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through cell-site location information.


In 2011, police officers arrested four men suspected of robbing a series of Radio Shack and T-Mobile stores in Detroit. One of the men confessed that, over the previous four months, the group (along with a rotating cast of getaway drivers and lookouts) had robbed nine different stores in Michigan and Ohio. The suspect identified 15 accomplices who had participated in the heists and gave the FBI some of their cell phone numbers. The FBI then reviewed his call records to identify additional numbers that he had called around the time of the robberies. Based on that information, the prosecutors applied for court orders under the Stored Communications Act to obtain cell phone records for petitioner Timothy Carpenter and several other suspects. That statute, as amended in 1994, permits the government to compel the disclosure of certain telecommunications records when it “offers specific and articulable facts showing that there are reasonable grounds to believe” that the records sought “are relevant and material to an ongoing criminal investigation.” Federal magistrate judges issued two orders directing Carpenter’s wireless carriers—MetroPCS and Sprint—to disclose cell/site sector information for Carpenter’s telephone at call origination and at call termination for incoming and outgoing calls during the four-month period when the string of robberies occurred. Altogether the government obtained 12,898 location points cataloging Carpenter’s movements—an average of 101 data points per day. Carpenter was charged with six counts of robbery and an additional six counts of carrying a firearm during a federal crime of violence. Prior to trial, Carpenter moved to suppress the cell-site data provided by the wireless carriers. He argued that the government’s seizure of the records violated the Fourth Amendment because they had been obtained without a warrant supported by probable cause. The district court denied the motion, and prosecutors used the records at trial to show that Carpenter's phone was near four of the robbery locations at the time those robberies occurred. Carpenter was convicted. On appeal, the United States Court of Appeals for the Sixth Circuit affirmed, holding that Carpenter lacked a reasonable expectation of privacy in the location information collected by the FBI because he had shared that information with his wireless carriers.


Was the government's acquisition of the cell-site data provided by the wireless carriers a violation of Carpenter’s Fourth Amendment rights?




The U.S. Supreme Court held that the government's acquisition from wireless carriers of Carpenter’s historical cell-site location information (CSLI) was a search under the Fourth Amendment. According to the Court, when the government accessed Carpenter’s CSLI, it invaded his reasonable expectation of privacy in the whole of his physical movements, and the fact that the government obtained the information from a third party did not overcome defendant's claim to Fourth Amendment protection. Thus, the decision was reversed.

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