A man the Justice Department says is a leader in the right-wing militia-type group known as the Oath Keepers was accused of “conspiracy” and other crimes in connection to the siege of Congress this month.

Thomas Edward Caldwell, a 65-year-old Virginian whom an FBI special agent said “appears to have a leadership role" within Oath Keepers, was arrested Tuesday. A Justice Department criminal affidavit said there was probable cause to believe he “knowingly and willfully entered into a conspiracy” to violate a number of federal laws, illegally entered the restricted Capitol grounds, sought to corruptly impede a congressional proceeding, engaged in disorderly conduct at the Capitol, and was “aiding and abetting the commission of these offenses against the United States.”