Senator Ron Wyden (D-OR) sent a letter to US Attorney General Merrick Garland with concerns about the “long-running dragnet surveillance program” that has allowed the government to obtain “trillions” of phone records for years, as first reported by Wired.

The letter states the White House pays AT&T to give all federal, state, local, and Tribal law enforcement agencies “the ability to request often-warrantless searches.” Senator Wyden expresses concerns about the legality of the surveillance program, which was first made public in 2013, and urges the public release of information about the project.