An anonymous reader quotes a report from the New York Times: When the Call Federal Credit Union outside Richmond, Va., was robbed at gunpoint in 2019, the suspect took $195,000 from the bank's vault and fled before the police arrived. A detective interviewed witnesses and reviewed the bank's security footage. But with no leads, the officer relied on a so-called geofence warrant to sweep up location data from all the cellphones in the vicinity of the bank for the 30 minutes before and after the robbery. The data he gathered eventually led to the identification and conviction of Okello T. Chatrie, now 31, a Jamaican immigrant who came to the United States in 2017. Geofence searches have become increasingly popular as a tool for law enforcement, but critics say they put at risk the personal data of everyday Americans and violate the Constitution. Mr. Chatrie challenged the use of a geofence warrant in his conviction, in a case that will be heard by the Supreme Court on Monday. The justices will examine how the Constitution's traditional protections apply to rapidly changing technology that has made it easier for the police to scoop up vast amounts of data to assemble a detailed look at a person's movements and activities. It has been eight years since the court last took up a major Fourth Amendment case involving the expectations of privacy for the millions of people carrying cellphones in the digital age. In that 2018 case, the court ruled that the government generally needs a warrant to collect location data drawn from cell towers about the customers of cellphone companies. The court has also limited the government's ability to use GPS devices to track suspects' movements, and it has required that law enforcement get a warrant to search individual cellphones. In Mr. Chatrie's case, the government did obtain a warrant, but one that his legal team said was overly broad, violating Fourth Amendment protections against unreasonable searches.Read more of this story at Slashdot.