A coalition of law enforcement agencies spearheaded by the FBI is hunting for anyone involved in Wednesday’s riots on Capitol Hill, and former special agents tell Fox News that advanced digital technology as well as traditional techniques will be used to find suspects.
FBI Director Christopher Wray said Thursday the bureau has deployed its "full investigative resources" to "aggressively pursue those involved" in Wednesday’s unrest.
Police said four people died as a violent mob of apparent Trump supporters stormed the U.S. Capitol, where Congress was tallying Electoral College votes that would confirm Joe Biden is president-elect.
Dozens of people, some armed with guns, roamed the halls of the federal building, smashed or dismantled property and barged into House and Senate leaders’ chambers. Meanwhile, Hill staffers and lawmakers were under lockdown, or hid behind chairs or under tables.
Benjamin Phillips, a 50-year-old Pennsylvania man; Rosanne Boylan, a 34-year-old Georgia woman; and Kevin Greeson, a 55-year-old from Alabama, died after suffering "medical emergencies" related to the breach, law enforcement officials said during a Thursday press conference.
"I’ve never seen anything like that," former FBI special agent in charge Andrew Arena told Fox News by phone on Thursday. "I was disgusted. I was disappointed. Saddened. I mean, it's just a flood of emotions to see that in our nation's capital. And I've spent two-thirds of my time with the FBI."
Arena led the FBI’s Detroit Division, which served all of Michigan, from 2007 to 2012, and previously worked as special agent in charge of criminal investigations at the FBI’s New York office. He now serves as executive director of the Detroit Crime Commission and is an adjunct professor at Thomas M. Cooley Law School at Western Michigan University.
Arena said the countless photos of people – many of whom were not wearing masks or face coverings – online and on social media will make identifying suspects easier. He believes the FBI’s tip line will be flooded with people who recognize someone in the photographs.
"The FBI hotline, tip line is getting thousands of calls today," he predicted. "Fortunately, a lot of these folks did not really disguise themselves very well. So, I think the majority of it is going to be citizens calling in and identifying people."
Arena said people often don’t think twice when sharing photos or information on their social media sites.
"That's where you get a lot of evidence these days," he said, "People tend to kind of bare their whole soul to everyone."
Investigators likely would look further at those individuals’ social media activity -- their friends and their recent whereabouts for clues and others possibly involved, explained Michael Tabman, a retired FBI special agent in charge who oversaw the Minneapolis Field Office.
"That's seeing not only what each person did, but they are also going to look at the criminal conspiracy – where people conspired together to commit this crime," Tabman told Fox News. "And even more importantly, is there more to come?"
Tabman worked as a police officer prior to joining the bureau and has since founded a corporate security consulting firm.
Facial recognition technology also could be advantageous in studying photographs and videos from Capitol Hill.
XRVision told Fox News in an emailed statement that soon after the riots erupted, the company "performed an analysis on the footage and identified several individuals." The company then shared that information with law enforcement.
Arena did not speak specifically to the FBI’s use of facial recognition technology.
On Thursday, Metropolitan Police Chief Robert Contee said of the 68 people arrested, only one was a Washington resident and 11 were from Maryland or Virginia. The department has since collected "numerous images of persons of interest" and is now seeking help from the public.
"We shared these images last night with the D.C. bids, the hotel associations and other community partners along with the FBI," Contee said. "We also have shared these images with the regional airport authorities."
The images are available online and on the police department’s website and social media platforms.
People traveling from another state to D.C. not only could face greater charges for crossing state lines, but also could be more easily identified if they traveled through airports, Tabman said Thursday.
And anyone making significant moves from location to location, Tabman said, is "leaving an electronic footprint somewhere."
"We're being picked up ... on somebody's camera, were checking into some terminal or computer that's going to steal our information," he said. "So, tracking that has become much easier."
When contacted on Thursday, U.S. Customs and Border Protection would not discuss its involvement, if any, in the investigation at airports and ports, and deferred all questions to the FBI.
The FBI is working with the Metropolitan Police Department, U.S. Capitol Police, and other state and federal law enforcement partners.
"We’re going to have our social media sleuths doing the things we just talked about – social media tracing. But this is boots on the ground," Tabman said. "We're going to be knocking on doors, talking to people, possibly executing search warrants, probably see these people's computers or other property."
He continued: "This is going to be a high priority because of the scrutiny and what this was – it was a violent attempt to destabilize the government."
Fox News' James Rogers contributed to this report.