Perhaps the most easily recognized interloper wore the same bearskin headdress with horns, and carried the same six-foot spear, as he did on his Facebook page. Prosecutors called it “distinctive attire” in charging documents.

These and more details gleaned from court documents reveal how the FBI has quickly identified more than 275 suspects — the number is expected to grow quickly — related to last week’s Capitol riot. More than 98 have been arrested, often with the aid of video taken or social media posted by the participants themselves. And investigators, academics and citizen sleuths are still combing though broadcast footage and websites such as Twitter Inc., YouTube and even archives of the now-defunct Parler platform favored by right-wing activists.

More than 140,000 pieces of digital media have been obtained by the FBI. “And we are scouring every one for investigative and intelligence leads,” Steven D’Antuono, assistant director in charge of the FBI’s Washington Field Office, told reporters. “We continue to ask for more.”