evidence: Following a pro-Trump mob storming the U.S. Capitol on Jan. 6, viral posts spread a groundless theory that members of "antifa" — not supporters of President Donald Trump — were actually behind the riot. [...] U.S. Capitol Police announced that 14 people were arrested on Jan. 6, most for unlawful entry. That’s in addition to the 69 individuals arrested by the D.C. Metropolitan Police Department, 41 of which were on Capitol grounds (but not all of those were inside), a spokesman told us. The latter department’s acting chief, Robert J. Contee III, said during a Jan. 7 press conference that he could not yet identify any particular groups involved. Federal authorities are also investigating. The FBI’s assistant director in charge of the FBI Washington field office, Steven D’Antuono, said in a Jan. 8 call with reporters that there was currently "no indication" that antifa activists had disguised themselves as Trump supporters and carried out the Capitol riot. [...] One Facebook post shared by more than 4,000 users claimed, "FYI These are NOT Trump supporters….Antifa THUGS." The post included a photo of the rioters inside the Capitol with an arrow pointing to a man wearing a headpiece with fur and horns.