Tuesday’s televised hearing of the House Select Committee investigating the January 6th domestic terrorist attack on Congress will feature a number of people associated with far-right extremist groups, including one person who described himself as the Oath Keepers’ “propagandist,” NBC News reports.

The committee will present evidence that Donald Trump’s tweet on December 19, 2020–“Peter Navarro releases 36-page report alleging election fraud ‘more than sufficient’ to swing victory to Trump … . A great report by Peter. Statistically impossible to have lost the 2020 Election. Big protest in D.C. on January 6th.  Be there, will be wild!”–was a beacon for violent nationalists groups to rally their members to attack Congress.

One of the expected witnesses is Jason Van Tatenhove, who was the national media director for the Oath Keepers from 2014 to 2017 and who denies continuing connections to the group.  Van Tatenhove is expected to describe how Oath Keepers leader Stewart Rhodes frequently bought into and manipulated conspiracy theories to motivate his members.

Members of the Proud Boys and other members of the Oath Keepers are also expected to testify either in person or on video during a session which will outline how Trump’s December 2020 tweet led to coordination between various groups and Trump’s personal advisors, and ultimately to the groups planning assaults on the Capitol, including collecting caches of weapons to violently take control, if needed.