Technology Law and Policy Clinic Project Leads to First-of-Its-Kind Brief in “Geofence” Warrants Case

December 12, 2019

A semester’s worth of research and legal writing by NYU Law’s Technology Law & Policy (TLP) Clinic recently served as a template in a high-profile, first-of-its-kind case, United States v. Chatrie, involving so-called “geofence” warrants.
In recent years, law enforcement has begun accessing the enormous troves of personal location data held by big tech companies, like Google’s “Sensorvault.”  The Sensorvault collects precise location data from hundreds of millions of Google Android devices as well as iPhones, iPads, and other devices with Google Maps installed.  Law enforcement obtains access to Sensorvault and similar databases through what are called “geofence” or “reverse” warrants.  These warrants are not limited to a particular suspect but instead give law enforcement wide-ranging access to location data from all users of Google (or similar location services) within a particular radius during some window of time.  Law enforcement can then sift through the location data of dozens or even hundreds of individuals’ devices, including individuals who have no tie to any criminal activity, to hunt for evidence.
In the 2018-19 academic year, two students from the TLP Clinic, Rachel Brooke and Morgan McCollum, represented the National Association of Criminal Defense Lawyers (NACDL) and were tasked with conducting factual research and drafting a legal argument for later use in cases around the country raising 4th Amendment challenges to law enforcement’s use of geofence warrants. Working with Michael Price, Senior Litigation Counsel for the NACDL’s Fourth Amendment Center, they drafted materials arguing that that geofence warrants violate the 4th Amendment’s protection against unreasonable searches, because the warrants are both overbroad and lack particularity, and therefore analogous to illegal general warrants and surveillance dragnets.
A year later, the students’ work served as the foundation for a brief filed in the Chatrie case.  In that case, Okello Chatrie has been charged with armed robbery based on Google Sensorvault data obtained by law enforcement via a geofence warrant.  Chatrie’s attorneys—the NACDL’s Price and Laura Koenig, a public defender in the Eastern District of Virginia—moved to suppress evidence obtained through the geofence warrant.  As their brief explains, the warrant “is the digital equivalent of searching every home in the neighborhood of a reported burglary, or searching the bags of every person walking along Broadway because of a theft in Times Square. Without the name or number of a single suspect, and without ever demonstrating any likelihood that Google even has data connected to a crime, law enforcement invades the privacy of tens or hundreds or thousands of individuals, just because they were in the area.”
Chatrie has attracted significant press attention, including stories by NBC News and the International Business Times, as the first case challenging the constitutionality of geofence warrants.  The government filed its opposition to Chatrie’s motion on November 19, and the case, United States v. Chatrie, No. 3:19-cr-130 (E.D. Va.), remains pending as of writing.  Through the research in the Chatrie brief, the TLP Clinic’s work may serve as a template for defendants in future cases involving evidence obtained through geofence warrants.