A man who authorities say is a leader of the far-right Oath Keepers militia group and helped organize a ring of other extremists and led them in the attack last month at the U.S. Capitol has held a top-secret security clearance for decades and previously worked for the FBI, his attorney said Monday.

Thomas Caldwell, who authorities believe holds a leadership role in the extremist group, worked as a section chief for the FBI from 2009 to 2010 after retiring from the Navy, his lawyer, Thomas Plofchan, wrote in a motion urging the judge to release him from jail while he awaits trial.

Read more: CBS News