The rioters who laid siege to the U.S. Capitol last week were planning to “capture and assassinate” elected officials, federal prosecutors said as they revealed chilling new details of the riot in court. U.S. prosecutors are seeking to detain Jacob Chansley, an insurrectionist from Arizona who was photographed wearing an animal headdress and standing at the dais that Vice President Mike Pence deserted when the rioters laid siege to the building. A court filing in Arizona on Thursday said Chansley had left a letter for Pence saying, “It’s only a matter of time, justice is coming.” “Strong evidence, including Chansley’s own words and actions at the Capitol, supports that the intent of the Capitol rioters was to capture and assassinate elected officials in the United States Government,” prosecutors said. The Arizona filing may offer a preview of more serious charges to come as the Capitol investigation ramps up in the coming weeks, said Harry Sandick, a former federal prosecutor in New York. “The government would not make that type of statement unless they thought they could prove it,” Sandick said. “The law is coming.” But at a press conference on Friday, the top U.S. prosecutor in Washington, Michael Sherwin, cautioned that federal investigators have found no direct evidence of organized teams of rioters plotting to capture and kill government officials at the Capitol. “There are bread crumbs of organization in terms of what was taking place outside the Capitol and inside,” he said. “This is going to take weeks if not months to find out the actual motivations of some of those groups.” While most of the cases so far involve relatively minor offenses like trespassing and disorderly conduct, Sherwin has promised a lengthy investigation that could lead to charges of seditious conspiracy and felony murder. Five people died in the riot, including a police officer who was reportedly bludgeoned with a fire extinguisher. Rioters stormed the Capitol to demand that President Donald Trump be declared the winner of the November election, after a speech in which Trump repeated a series of discredited claims of voter fraud. Concerned over the possibility of further violence in Washington, authorities have called on more than 25,000 law enforcement, military and intelligence personnel to provide security for President-elect Joe Biden’s swearing-in ceremony on Jan. 20. Before his arrest, Chansley told law enforcement officials that his letter to Pence was not a threat, according to the filing in Arizona. But he also referred to the vice president as a “child-trafficking traitor” and said he hoped to return to Washington to protest during Biden’s inauguration next week. “Although he stated his note was not a threat, the government strongly disagrees,” prosecutors said, urging a federal judge to keep Chansley in custody. Chansley has been charged with obstruction of an official proceeding, entering and remaining in a restricted building, and disorderly and disruptive conduct, among other charges. A public defender representing Chansley in Arizona didn’t immediately respond to a request for comment. In recent days, U.S. prosecutors have ramped up the investigation into last week’s riot at the Capitol, with nearly 300 suspects under scrutiny, Sherwin said at the press conference. It’s one of the most expansive criminal investigations in the history of the Justice Department, with a wide assortment of agencies helping to build cases, including the Federal Bureau of Investigation and the U.S. Marshals. All 56 FBI field offices are involved. Subscribe to our YouTube channel: https://bit.ly/2TwO8Gm Bloomberg Quicktake brings you live global news and original shows spanning business, technology, politics and culture. Make sense of the stories changing your business and your world. To watch complete coverage on Bloomberg Quicktake 24/7, visit http://www.bloomberg.com/qt/live, or watch on Apple TV, Roku, Samsung Smart TV, Fire TV and Android TV on the Bloomberg app. Have a story to tell? Fill out this survey for a chance to have it featured on Bloomberg Quicktake: https://cor.us/surveys/27AF30 Connect with us on… YouTube: https://www.youtube.com/user/Bloomberg Breaking News on YouTube: https://www.youtube.com/c/BloombergQuickTakeNews Twitter: https://twitter.com/quicktake Facebook: https://www.facebook.com/quicktake Instagram: https://www.instagram.com/quicktake