US Supreme Court weighs lawfulness of 'geofence' warrants in crime probes

The U.S. Supreme Court heard arguments ​on Monday over whether law enforcement's use of a "geofence" warrant to nab data from cellphones near ​the scene of a Virginia armed robbery violated the U.S. Constitution's Fourth ‌Amendment ​bar on unreasonable searches. The justices were hearing an appeal by defendant Okello Chatrie, who conditionally pleaded guilty in 2022 to robbing a Midlothian, Virginia credit union while reserving his right to make his case for suppressing evidence gleaned from what he argues was an illegal search.

The U.S. Supreme Court heard arguments ​on Monday over whether law enforcement's use of a "geofence" warrant to nab data from cellphones near ​the scene of a Virginia armed robbery violated the U.S. Constitution's Fourth ‌Amendment ​bar on unreasonable searches.

The justices were hearing an appeal by defendant Okello Chatrie, who conditionally pleaded guilty in 2022 to robbing a Midlothian, Virginia credit union while reserving his right to make his case for suppressing evidence gleaned from what he argues was an illegal search. President Donald Trump's administration is defending the investigative method ‌that helped secure Chatrie's sentence of nearly 12 years in prison for brandishing a gun and making off with $195,000. Court-approved geofence warrants compel third-party companies - such as Alphabet's Google in Chatrie's case - to search customer location data for mobile devices that were near a crime scene.

Investigators are typically handed an anonymized list to start with, before it is narrowed down in a multi-step process culminating with the company providing account holder information to police for potential leads on ‌suspects. The case argued on Monday highlights tensions between an 18th century constitutional provision that safeguards the "right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures" ‌and digital-age technology that is transforming how crime is investigated.

Authorities in Chatrie's case had exhausted all other leads when they sought a court-approved geofence warrant based on footage of the robber using a cellphone at the credit union. Google location data placed Chatrie at the crime scene in addition to 18 other users who, like Chatrie, had opted in to the company's "location history" feature and were within a 150-meter (492-foot) radius of the credit union within a one-hour window of the May 2019 robbery. Further investigation of residences linked to Chatrie led authorities to ⁠discover what ​the government described as two "robbery-style demand notes" in his ⁠bedroom, a pistol and nearly $100,000 that included bills wrapped in bands signed by the credit union teller who was targeted in the robbery.

Lawyers for Chatrie contend in court papers that geofencing amounts to a dragnet search that exposes mass amounts of private information ⁠to the government and lacks the specificity required by the Fourth Amendment. Justice Department lawyers countered that Chatrie's opting in to Google's location history stripped him of any expectation that his data would remain private. Moreover, they argued, police had "probable cause" to ​believe that Google had information that could help identify the robber, accomplices and witnesses.

Google, which is not a party to the case, filed a brief arguing for the "robust application of the Fourth Amendment ⁠to the modern digital context." The company said it has objected to more than 3,000 geofence warrants on constitutional grounds and that it can no longer respond to such warrants after moving location history retention to users' devices. Previously, about one in three active Google users had ⁠the location ​history feature enabled, a population one judge estimated to be around 500 million people, according to court papers.

Virginia-based U.S. District Judge Mary Lauck found that the geofence warrant used in Chatrie's case violated the Fourth Amendment prohibition on unreasonable searches. However, the judge denied his evidence suppression request, finding that investigators had acted with a good faith belief that their actions were lawful. The full bench of the Richmond-based Fourth U.S. Circuit Court of ⁠Appeals affirmed Lauck's decision, prompting Chatrie's appeal to the justices.

The Supreme Court in 2018 imposed limits on the ability of police to obtain cellphone data pinpointing the past location of criminal suspects in a victory ⁠for digital privacy advocates and a setback for law enforcement ⁠authorities. In a 5-4 ruling, the court said police generally need a court-approved warrant to get the data, setting a higher legal hurdle than previously existed under federal law. In Chatrie's case, the justices agreed to decide whether geofence warrants are unconstitutional but declined to hear his evidence-exclusion claim. If Chatrie wins the constitutional argument, his ‌case would likely be returned to ‌the district court for further proceedings.

A Supreme Court ruling in the case is expected by around the end of ​June.