The FBI has admitted to buying Americans’ location data from advertising companies, raising concerns across the spectrum.

The Supreme Court ruled in 2018 that law enforcement agencies were required to obtain a warrant before tracking Americans’ locations using cell phone data. The case was a major blow to the FBI, and other agencies, many of whom had relied on warrantless location tracking.

It appears the FBI has found a way around the Supreme Court ruling, purchasing location data from advertising companies, according to Wired. The revelation came in the course of a US Senate hearing.

Senator Ron Wyden, a well-known privacy advocate, asked FBI Director Christopher Wray if the agency used commercial location data.

“Does the FBI purchase US phone-geolocation information?” Wyden asked.

“To my knowledge, we do not currently purchase commercial database information that includes location data derived from internet advertising,” Wray responded. “I understand that we previously—as in the past—purchased some such information for a specific national security pilot project. But that’s not been active for some time.”

Director Wray did say the FBI now relies on a “court-authorized process,” but did not go into detail regarding what that meant.

Even so, many were quick to jump on Wray’s admission, pointing out the dangerous precedent it sets.

“The public needs to know who gave the go-ahead for this purchase, why, and what other agencies have done or are trying to do the same,” said Sean Vitka, a policy attorney at Demand Progress. He also said Congress should ban the practice.