Three officers have been suspended and 17 more are under investigation, according to a senior congressional aide.

The department is accustomed to being shielded from the type of public disclosure that is routine for ordinary police agencies. But since last week’s rampage, the department’s chief and two other top security officials have resigned, and its congressional overseers have pressed for answers.

On Wednesday, Rep. Tim Ryan, D-Ohio, complained that the agency was a “black box.”

“We’re having a hell of a time getting information from Capitol Police leadership,” said Ryan, who chairs the House committee that oversees the department’s budget. “We fund the Capitol Police. Congress funds the Capitol Police through the Appropriations Committee. We deserve to know and understand what the hell is going on.”