A year after the worst attack on the U.S. Capitol since the British burned it nearly 208 years ago, the FBI hasn't stopped working to identify the rioters who stormed the building on Jan. 6, 2021.
Agents and analysts are combing through tens of thousands of photos and videos, using facial recognition software and cellphone records that allow them to plot the movement of people inside the Capitol — the largest such use of that technique.
Federal criminal charges have been filed against 705 people, and about one fourth of them have pleaded guilty. Judges have imposed sentences on roughly 70 defendants, and 31 of them have been ordered to serve time behind bars for periods ranging from a few days to just over five years.
"The Justice Department remains committed to holding all January 6th perpetrators, at any level, accountable under law, whether they were present that day or were otherwise criminally responsible for the assault on our democracy," Attorney General Merrick Garland said Wednesday in remarks thanking department officials for their work on the riot cases. "We will follow the facts wherever they lead."
A priority now for the FBI is identifying more than 250 people seen on photos and videos assaulting police officers inside and outside the building.
"The attacks happened all over the Capitol grounds," said Steven D'Antuono, the FBI's assistant director in charge of its Washington field office. "It wasn't just one punch and done. It was multiple times that these officers, men and women, were assaulted."
At least 140 officers were attacked. Videos on the FBI website, FBI.gov, show rioters using a long probe to administer shocks, beating officers with a pole, and spraying them with chemical irritants.
The public response to the FBI's requests for help produced hundreds of thousands of tips, D'Antuono said, and not just from people who thought they recognize rioters in the photos and videos.
"We've had had restaurant workers turn somebody in because they overheard them talking about it. We've had ride-share drivers who heard or saw something out of the ordinary and gave us a tip."
Researchers led by Robert Pape, a political science professor at the University of Chicago, studied data on the rioters and concluded that they represent a mainstream political movement and were not simply hardcore white supremacists.
"Our analysis shows that we are dealing with a new kind of right-wing movement, one that is demographically closer to an average American than an average right-wing extremist and indicating that far-right support for political violence is moving into the mainstream," said a report Pape issued on Wednesday.
His researchers found, for example, that 43 percent of the rioters charged could be considered white-collar workers, and more than a quarter owned their own businesses.
But some big questions remain, including whether there actually was a plan well in advance to storm the Capitol, or whether it was a case of seizing the moment.
Seamus Hughes, deputy director of the Program on Extremism at George Washington University, says it's important to figure it out.
"It does matter in terms of a record of history, to get a sense of what this event was all about," he said. "Was it a perfect storm of a failure of security, of extremists all coalescing around the Capitol, or was this something greater?"
Members of the far-right Proud Boys and Oath Keepers have been charged with conspiracy, but court documents say they were preparing for violence in the streets.
And the FBI has yet to figure out who planted two pipe bombs the night before the riot at Republican and Democratic national headquarters near the Capitol. Agents report no breakthroughs so far, despite releasing surveillance video showing the suspected bomber that night on Capitol Hill.
One of the difficulties, D'Antuono said, is that whoever did it was carefully disguised. "They're covered from head to toe," he said. "They have a hoodie on, glasses, a mask, fully clothed. It's hard to identify that person. But we've done over 900 interviews in this investigation."
He said the bombs were correctly made and could have exploded, though it's not clear why the devices did not go off.
"It's extremely important to find this person, because these devices were something that could have hurt somebody," he said. "This person's still out there."