McDermott Will & Schulte files amicus brief for digital privacy and civil liberties organizations in Ninth Circuit cell tower dump case

Global law firm McDermott Will & Schulte filed an amicus curiae brief on behalf of the Center for Democracy & Technology, Defending Rights & Dissent, the Surveillance Technology Oversight Project, and the Electronic Privacy Information Center in United States v. Spurlock, a pending US Court of Appeals for the Ninth Circuit case concerning the constitutionality of a cell tower dump warrant. The brief was filed in support of defendant-appellant Cory Spurlock and reversal.

At issue is a warrant obtained by the Mono County Sheriff’s Office directing two telecommunications companies to produce a “tower dump” —cell site location information for every device that connected to cell towers near two rural highway mile markers over a six-hour window. The brief states that the warrant identified no suspect, device, or phone number in advance and returned location records for 1,686 devices.

McDermott’s brief argues that the warrant was an unconstitutional general warrant because it authorized a broad search of Fourth Amendment-protected location information without specific suspicion. The brief contends that cell tower dumps can reveal sensitive location information with increasing precision and that Supreme Court precedent, including Carpenter v. United States and Chatrie v. United States, protects electronically generated location information from overbroad government searches.

The brief further argues that the government cannot justify an overbroad digital dragnet merely because the search later identifies a suspect. It warns that approving the warrant could open the door to other expansive “reverse” warrants that target groups of individuals based on location data, internet search keywords, IP (Internet Protocol) addresses, and artificial intelligence prompts.

The McDermott team representing the Center for Democracy & Technology, Defending Rights & Dissent, the Surveillance Technology Oversight Project, and the Electronic Privacy Information Center includes Katelyn Ringrose, Raja Chatterjee, Robert Duffy, Brian Long, and Jordan Zaia.