The alleged gunman who opened fire at the White House Correspondents' dinner on Saturday is due in court Monday as lawmakers question security measures at the event.Authorities apprehended 31-year-old Cole Tomas Allen of Torrenc e, California, before he could enter the ballroom. The room held 2,300 guests, including President Donald Trump and many cabinet members in the line of succession.RELATED STORY | Alleged manifesto reveals suspect targeted Trump officials at Correspondents' DinnerOne officer was shot in their bullet-resistant vest amid the chaos but is expected to recover. Inside the ballroom, attendees heard shots before Secret Service agents stormed the stage to protect Trump and others.Scripps News learned that Allen sprinted through a security checkpoint and left behind a manifesto expressing a desire to target top Trump administration officials. Family members told investigators Allen had a tendency to make radical statements. Acting Attorney General Todd Blanche said Allen will face two charges: using a firearm during a crime of violence and assault on a federal officer with a dangerous weapon. Blanche added that it appears Allen traveled by train from Los Angeles to Chicago and then to Washington, D.C., checking into the event's hotel two days prior.RELATED STORY | 'I'll never forget': Trump dinner performer details mayhem as shooting unfoldedOn Capitol Hill, lawmakers immediately began questioning security. Republican Sen. Chuck Grassley said in a statement on social media that he plans to set up a briefing with Secret Service leadership regarding security protocols and related law enforcement activities. Other questions raised include whether the magnetometers used for the event were properly placed and whether the perimeter was truly secure. ...read more read less