RICHMOND, Va. (AP) — A warrant that used Google location history to find people near the scene of a 2019 bank robbery violated their constitutional protection against unreasonable searches, a federal judge has ruled.

The decision — believed to be the first of its kind — could make it more difficult for police to continue using an investigative technique that has exploded in popularity in recent years, privacy experts say.

The ruling came earlier this month in a closely watched Virginia case in which the robbery suspect argued that the use of a “geofence warrant” violated the Fourth Amendment. Geofence warrants seek location data on every person within a specific location over a certain period of time. To work, those people must be using cellphones or other electronic devices that have the location history feature enabled.

U.S. District Judge Hannah Lauck found that the warrant violated the constitution by gathering the location history of people near the bank without having any evidence that they had anything to do with the robbery.

“The warrant simply did not include any facts to establish probable cause to collect such broad and intrusive data from each of these individuals,” Lauck wrote in her ruling.

The judge said she was not ruling on whether geofence warrants can ever satisfy the Fourth Amendment, but privacy advocates said the decision could make it more difficult for police to persuade magistrates to grant such warrants.

“She’s saying that’s a general search that’s just sweeping up people, most of whom have nothing to do with the thing you are investigating,” said Jennifer Stisa Granick, surveillance and cybersecurity counsel for the American Civil Liberties Union. “You have to seriously consider the impact on uninvolved people and their privacy, and the balance of power between people and law enforcement.”

Jennifer Lynch, surveillance litigation director for the Electronic Frontier Foundation, a nonprofit digital rights group, said attorneys around the country could cite the ruling in their own cases because it is believed to be the first time a federal district court judge has ruled on the constitutionality of a geofence warrant.

“It’s helpful to other judges to see how a judge has dealt with this, especially since the technology is so new,” Lynch said.

Police say geofence warrants are a useful investigatory technique that has helped lead them to suspects in an array of crimes around the country, including home invasions in Minnesota, a slaying in Georgia and a fatal shooting in North Carolina. Defense attorneys, however, say they ensnare innocent people and violate the privacy of anyone whose cellphone happens to be in the vicinity of where a crime occurred.

In the Virginia case, a man walked into the Call Federal Credit Union in Midlothian on May 20, 2019, waved a gun and threatened to kill a teller’s family if he did not get at least $100,000 in cash. The robber, who was seen on surveillance video holding a cellphone in his hand, escaped with $195,000.

After following a couple of leads that didn’t pan out, police went to a magistrate judge and obtained a geofence search warrant, seeking location history from Google for any devices located within a 150-meter (164-yard) radius of the bank around the time of the robbery.

Google turned over location data for 19 devices without providing any identifying information. Police then narrowed down their request to three devices, for which Google provided the information. Police arrested Okello Chatrie, who was charged with armed robbery.

Bank cameras showed the robber came and went from an area where a church worker saw a suspicious person. Chatrie’s location history matched these movements.

Chatrie’s lawyers declined to comment on Lauck’s ruling. In court papers, they called the warrant the equivalent of “searching the bags of every person walking along Broadway because of a theft in Times Square.”

Google said it is reviewing the court’s ruling. “We vigorously protect the privacy of our users, including by pushing back on overly broad requests, while supporting the important work of law enforcement,” the company said in a statement.

In a legal brief, Google said geofence requests jumped 1,500% from 2017 to 2018, and another 500% from 2018 to 2019. Google now reports that geofence warrants make up more than 25% of all the warrants Google receives in the U.S., the judge wrote in her ruling.

Prosecutors declined to comment. In court documents, they argued Chatrie had no reasonable expectation of privacy since he voluntarily opted in to Google’s Location History.

Lauck urged “legislative action” on the issue, noting that there is currently no law prohibiting Google and other companies from collecting and using vast amounts of data from their customers.