US Law Enforcement Authorities Step Up Investigation of Capitol Hill RiotsU.S. law enforcement authorities are stepping up a criminal investigation into Wednesday's attack on the U.S. Capitol by supporters of President Donald Trump that could include his role in instigating the mob. Acting U.S. Attorney for the District of Columbia Michael Sherwin said a total of 55 people have been charged with various crimes, including 15 people in connection with rioting at the Capitol. Trump has been widely condemned for inciting the violence by imploring supporters angry over his electoral loss to march on the Capitol. In a rare rebuke, former Attorney General William Barr, a staunch Trump ally while in office, said in a statement that the president's conduct "was a betrayal to his office and supporters." Asked if federal prosecutors were examining Trump's role in inciting the violent assault on the Capitol, Sherwin said, "We're looking at all actors here and anyone that had a role and the evidence fits the elements of a crime, they're going to be charged." Trump told a crowd of supporters gathered near the White House on Wednesday morning to "fight like hell" before urging them to march on the Capitol, where lawmakers were deliberating over the certification of the electoral victory of Democratic President-elect Joe Biden and Vice President-elect Kamala Harris. The president is facing calls to resign over the incident less than two weeks before his term ends on January 20. The attack left five people dead, including U.S. Capitol Police officer Brian C. Sicknick. Dozens of people were injured in Wednesday's violence. Arrests are 'just the beginning' On Friday, Acting Attorney General Jeffrey Rosen issued a statement saying, "the FBI and Metropolitan Police Department will jointly investigate the case and the Department of Justice will spare no resources in investigating and holding accountable those responsible." Sherwin said prosecutors are aggressively pursuing the perpetrators and are not ruling out bringing charges of sedition. "Make no mistake about it: This was obviously a very dangerous situation," Sherwin told reporters. "We're aggressively trying to address these cases as soon as possible, and make no mistake about it, even though we just teed up 15 cases, I think that's a good start, but it's in no regard the end." The federal charges against those arrested include theft of government property and firearms violations. One man was arrested near the U.S. Capitol on charges of carrying a semi-automatic assault weapon and 11 Molotov cocktails that were "ready to go," Sherwin said. He added the arrests are "just the beginning" of a potentially monthslong investigation. Because all but a handful of the hundreds of rioters who stormed the Capitol were allowed by Capitol Police to leave, the effort to identify and arrest the perpetrators could take months, perhaps all year. He said hundreds of investigators are combing surveillance videos and social media footage to identify the perpetrators. "We'll aggressively charge these cases," Sherwin said. Rosen said the Justice Department "is committed to ensuring that those responsible for this attack on our government and the rule of law face the full consequences of their actions under the law." "Our criminal prosecutors have been working throughout the night with special agents and investigators from the U.S. Capitol Police, FBI, ATF, Metropolitan Police Department and the public to gather the evidence, identify perpetrators and charge federal crimes where warranted," Rosen said in a statement Thursday. Incriminating evidence The brazen assault, the first mass violent attack on the Capitol Building in more than two centuries, began with hundreds of supporters of Trump storming the Capitol while members of Congress were meeting to certify Biden's win in the November 3 election. Capitol Police said "thousands of individuals" were involved "in violent riotous actions," attacking law enforcement officers with metal pipes, chemical irritants and other weapons. In a video posted late Thursday on Twitter, Trump addressed the "heinous attack on the United States Capitol," saying he was "outraged by the violence, lawlessness and mayhem." Sherwin stopped short of second-guessing the Capitol Police's decision not to arrest the rioters at the scene, but he said the failure has made it more difficult for federal investigators to track down and arrest the perpetrators. Many left behind incriminating evidence in the form of videos and photographs posted on social media. One QAnon supporter was photographed in the Senate chamber. Another Trump supporter had his photograph taken in Speaker Nancy Pelosi's office. Jordan Strauss, a former federal prosecutor and now a managing director with Kroll, a risk management consultancy, said the videos and photographs offer a "plethora of evidence" that prosecutors can use to bring charges. "A lot of people livestreamed their crimes while they were committing them," Strauss said. Potential charges The rioters could face several federal charges, from destruction of property to threatening members of Congress and sedition, he said. Sherwin said no charges, including sedition, are off the table. Sedition is the act of opposing government authority by force. Barr raised the prospects of bringing sedition charges against anti-police protesters in a memo to federal prosecutors last summer. Strauss said prosecutors will likely opt for "cleaner" charges that don't "risk infringing on First Amendment issues or allowing for an individual to claim that there's some sort of political prosecution." Joel Hirschhorn, a criminal defense attorney, said arresting and charging every rioter is going to be virtually impossible. "I think anyone who was inside the Capitol building is at risk because that was a trespass on government property," Hirschhorn said. "Will they be able to prosecute all of them? No, that's an impossibility."