Hours after he was sworn in as attorney general, Merrick Garland and his deputies gathered in a wood-paneled conference room in the Justice Department for a private briefing on the investigation he had promised to make his highest priority: bringing to justice those responsible for the attack on the U.S. Capitol on Jan. 6, 2021.

In the two months since the siege, federal agents had conducted 709 searches, charged 278 rioters and identified 885 likely suspects, said Michael R. Sherwin, then-acting U.S. attorney for the District of Columbia, ticking through a slide presentation. Garland and some of his deputies nodded approvingly at the stats, and the new attorney general called the progress “remarkable,” according to people in the room.

Sherwin’s office, with the help of the FBI, was responsible for prosecuting all crimes stemming from the Jan. 6 attack. He had made headlines the day after by refusing to rule out the possibility that President