WASHINGTON — Newly unearthed footage from Jan. 6, 2021, appears to show a rioter — a man identified in an NBC News story nearly two years ago — firing a gun into the air outside the Capitol during the attack. Online sleuths who have aided in hundreds of Jan. 6 prosecutions say he is the same man they identified to the FBI who is currently individual No. 200 on the bureau’s Capitol Violence page, which he first appeared on three years ago. Videos and photographs from the Capitol on Jan. 6 showed him with what appears to be a gun...