WASHINGTON —At 4:50 p.m. on May 20, 2019, an armed man holding a cell phone walked into the Midlothian, Virginia, branch of the Call Federal Credit Union and handed a note to a teller demanding cash.

At one point brandishing the gun, the man ordered the manager to open the safe. He walked out with $195,000.

Police officers were initially stumped when trying to figure out the identity of the robber, setting off a chain of events that led to a Supreme Court hearing on Monday, the latest in a series of cases on how new technology interacts with the Constitution's protection of individual rights.

The detective in charge was able to identify Okello Chatrie as the prime suspect by obtaining data from Google about cell phone users in the vicinity of the bank at the time of the crime.

A federal judge had approved what is known as a "geofence warrant" that allows police officers to seek such information even when they do not have a specific suspect in mind.

Google initially identified 19 users, but the officer ultimately narrowed his search down to Chatrie, whose phone had its Google "Location History" setting switched on. This feature is used for apps such as Google Maps. The data showed he was in or near the location in question ten minutes before the robbery and then departed soon after.

After further investigation, Chatrie ultimately pleaded guilty to federal charges of armed robbery and brandishing a firearm, and he was sentenced to almost 12 years in prison. But he reserved the right to appeal on the issue now before the Supreme Court: Did the broad request to Google violate his right to be free from unlawful searches and seizures under the Constitution's Fourth Amendment?

The Supreme Court has, in several previous cases, had to deal with similar questions about how the Fourth Amendment applies to new technology, ranging from wiretaps and thermal imaging to GPS tracking devices. In a similar case, the court ruled in 2017 that warrants are required to obtain location information derived from data picked up from cell phone towers.

The Chatrie case involves a broader, open-ended search, which privacy advocates refer to as a dragnet that pulls in information from sometimes hundreds of innocent people. A geofence warrant was infamously used to identify supporters of President Donald Trump who broke into the Capitol on Jan 6, 2021.

"It's the stuff authoritarian nightmares are made of," Jake Karr, a lawyer at the Knight First Amendment Institute, said in an interview.

The Trump administration, represented by Solicitor General D. John Sauer, is defending the practice, arguing that no search took place at all, meaning a warrant is not required. That is despite the fact that officers did have one in Chatrie's case.

If the court were to find that geofence searches do not require a warrant, it would open the door to government abuse that could infringe upon free speech rights by, for example, targeting protesters, Karr added.

The Justice Department argues, among other things, that people do not have an expectation of privacy when it comes to such information, in part because Chatrie voluntarily shared it with Google.

Even assuming a warrant is required, the one issued in Chatrie's case was lawful because law enforcement had "probable cause to believe that Google had information that would help identify the cellphone-using robber," Sauer wrote in court papers.

Although the case could have broad ramifications in the law, Google has since changed its storage policies. Now, location history is stored on an individual's device, not by Google itself on its servers. That means the company "can no longer respond to geofence warrants based on Location History data," its lawyers said in a brief filed in the case.