This week, the U.S. Supreme Court heard oral arguments in Carpenter v. United States, where the question presented is whether the Fourth Amendment permits the warrantless seizure and search of a user’s cellphone location and movement information.

In Carpenter, law enforcement officials were provided with several phone numbers by an individual involved in a series of armed robberies. One of the numbers belonged to the petitioner. Officials used this information to track the location and movement of Carpenter for 127 days through his cellphone data. They relied on the Stored Communications Act, a 1986 law that allows phone companies to disclose records to the government.

The SCA authorizes the issuance of a disclosure order whenever the government “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.” 18 U.S.C. § 2703(d). The government does not need to show probable cause that a crime has been committed to retrieve information under the SCA.

Read the transcript of the oral arguments.