During the January 6, 2021 Joint Session of Congress to certify the Electoral College ballots, while tens of thousands peaceful protesters rallied in support of President Trump outside the capitol, chartered vans of Antifa were escorted by state police in black, unmarked SUVs into the midst of the crowd. Capitol Police then removed barriers and waved the crowd in to the Capitol steps. Antifa rioters proceeded to break windows on the U.S. Capitol building and storm the premises. Facial recognition technology identified Antifa members, who had used disguises to infiltrate a pro-Trump protest group, as storming the building.
[note: the citation provided at  claims that the identification of Antifa members was an error and has corrected it.]