In taking the monumental step of charging a former president with attempting to steal an American election, Jack Smith, the Justice Department special counsel, relied on an extraordinary narrative, but one the country knew well.

For a year and a half, the special House committee investigating the Jan. 6, 2021, attack on the Capitol introduced Americans to a sprawling cast of characters and laid out in painstaking detail the many ways in which former President Donald J. Trump tried to overturn the 2020 election. In doing so, it provided a road map of sorts for the 45-page indictment Mr. Smith released on Tuesday.

“In a lot of ways, the committee’s work provided this path,” said Soumya Dayananda, who served as a senior investigator for the House Jan. 6 panel. “The committee served as educating the country about what the former president did, and this is finally accountability. The congressional committee wasn’t going to be able to bring accountability; that was in the hands of the Department of Justice.”