Here's what we know about links between extremists and Trump allies

The congressional committee investigating the Jan. 6, 2021 attack on the Capitol will focus on the role of QAnon and extremist groups like the Oath Keepers and Proud Boys in its upcoming hearing. Prosecutors have identified the man at the center of this photograph as a QAnon-supporter named Douglas Jensen. Jensen has pleaded not guilty to all charges. (Manuel Balce Ceneta/AP)

Tuesday's hearing of the Select Committee to Investigate the January 6th Attack on the United States Capitol will focus on the role of the pro-Trump conspiracy theory known as QAnon, as well as the role of extremist groups like the Proud Boys and the Oath Keepers, aides to the committee said. A key area of inquiry for congressional investigators has been possible ties between former President Trump and his allies and far-right extremists. And aides said the committee would present new evidence about how Trump's tweet calling for a "big protest" on Jan. 6th served as a kind of call to arms. "Be there, will be wild!" Trump tweeted.

A former spokesperson for the Oath Keepers is slated to testify publicly as part of Tuesday's hearing. The spokesperson, Jason Van Tatenhove, told Colorado TV station KDVR he had served as the Oath Keepers' "propagandist" starting in 2014, but separated from the group several years before the attack on the Capitol.