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Quartavious Davis v. United States (Amicus Brief)

The Brennan Center urges the Supreme Court to take a case about whether the Fourth Amendment requires law enforcement to obtain a warrant to access historical information about the location of an individual’s cell phone.

Published: September 1, 2015

Quartavious Davis was convicted of armed robbery based in part on 67 days of historical cell site location data obtained without a warrant. He has petitioned the Supreme Court to grant a writ of certiorari. The Brennan Center—in conjunction with the Electronic Frontier Foundation, the Center for Democracy and Technology, the Constitution Project, and the National Association of Criminal Defense Lawyers—has filed a brief supporting his petition.

The brief argues that cell site data paints a revealing picture of a person’s movements and that this data is increasingly being accessed by law enforcement without a warrant. It also notes that there is a circuit split on whether access to this data requires a warrant. It therefore urges the Supreme Court to hear the case and decide that the Fourth Amendment requires law enforcement to obtain a warrant to access individuals’ cell site location information.

More than 90% of American adults have a cell phone. Cell phones work by sending radio signals to cell towers. The towers record the “site,” or side of the tower, that received the signal. Modern cell phones are constantly exchanging data with cell towers, even in the absence of user activity such as placing a phone call or sending a text; for instance, even applications running in the background on a smartphone can generate location information. In turn, these communications with cell towers create a detailed record of where and when the phone, and its owner, has travelled.

In United States v. Jones, five justices found that 28 days of GPS tracking of a vehicle was problematic, citing the length of the period and the detailed information gathered about movements and associations. Cell-site data is even more worrying, as a phone is kept closer to the person than a car, collects longer periods of data, and allows reconstruction of past movements. Furthermore, it is gathered for all persons, not just those under law enforcement investigation.

This is a critical issue for the Supreme Court to address now because law enforcement requests for location data are rapidly increasing. Based on current rates, AT&T is projected to receive 75,946 law enforcement requests for location information in 2015; Verizon will receive 6,280 requests for “cell tower dumps,” or all information from a particular tower. Most of these requests are made with court orders that only require a showing that the material is “relevant and material” to an ongoing criminal investigation, rather than a warrant based on probable cause that evidence of criminal activity will be found.

The question of warrantless access to cell-site location records has been answered by federal and state courts across the country in conflicting ways. The U.S. Court of Appeals for the Eleventh Circuit, sitting en banc in this case, found no expectation of privacy in these records, meaning law enforcement in Georgia (as well as Alabama and Florida) do not need a warrant to access them. But for law enforcement in nearby states, the U.S. Court of Appeals for the Fourth Circuit reached the opposite conclusion in United States v. Graham, finding an expectation of privacy in these records and requiring law enforcement to use a warrant to obtain them.

This confusion not only means the public is left with differing legal protection under federal law, but also creates a risk of uncertainty for law enforcement. To resolve this confusion, the Supreme Court should grant a writ of certiorari and find that the Fourth Amendment requires law enforcement to get a warrant to access cell-site information.

Read the brief here.