The FBI used billing records from an internet social media app to unmask US airman Jack Teixeira as a suspect over the leak of top-secret military documents, it has been revealed.
Court documents made public on Friday showed investigators identified the Massachusetts Air National Guardsman, 21, using information on the Discord chat platform.
The leak is believed to have started on its servers, which are frequently used by people who play online games.
Classified information is said to range from briefing slides mapping out military positions in Ukraine to consideration of what circumstances Russian President Vladimir Putin might use nuclear weapons.
Discord said it was cooperating with the bureau, according to an FBI affidavit unsealed on Friday.
The document says the FBI interviewed an unnamed person familiar with Teixeira’s posts on Monday.