The messages showed that F.B.I. investigators took normal bureaucratic steps and precautions when opening an extraordinarily sensitive inquiry into Mr. Trump’s attempts to overturn the 2020 election.

Ed Martin, a longtime advocate for Jan. 6 defendants recently named to run the prosecutors’ office, sought to undo a judge’s order barring Stewart Rhodes from visiting Washington.

President Trump pardoned men who violently attacked police officers on Jan. 6 along with nearly 1,600 other people who had been charged in connection with the riot. But his grant of clemency did not erase the video evidence of their crimes.

Kash Patel, Donald J. Trump’s choice to run the bureau, has made a series of spurious assertions about the Russia, Jan. 6 and classified documents inquiries.

Two prominent far-right extremists with central roles in the Capitol attack, Enrique Tarrio of the Proud Boys and Stewart Rhodes of the Oath Keepers militia, have been set free.

The move, in effect, validated the far-right leader’s defiant claim that his criminal prosecution was a kind of political persecution.

The extraordinary pardons and commutations extended to those who committed both violent and nonviolent crimes on Jan. 6, including assaulting police officers and seditious conspiracy.

Officer Daniel Hodges said he had come to grips with the idea that his professional duty now required him to protect a man whose supporters beat him, kicked him and tried to gouge his eyes out in 2021.

At least eight rioters who have faced criminal charges have been granted permission to attend. Most were accused of relatively minor offenses.

The Justice Department now enters a second Trump administration with less authority to pursue a president than it has had in half a century.

Jack Smith wrote that Donald Trump would have been convicted had the case been allowed to proceed and explained why he didn’t pursue charges of incitement of the Jan. 6 riot at the Capitol.

Judge Aileen M. Cannon, who dismissed the classified documents case, blocked a volume about that matter from being shown to Congress but allowed the release of a volume about the election case.

Mr. Smith, a special counsel appointed by Attorney General Merrick B. Garland, had signaled that he would step down before Donald J. Trump’s inauguration.

But in a court filing, the department indicated that it would release a separate report about Donald J. Trump’s efforts to overturn the 2020 election as soon as possible.

Judge Aileen M. Cannon, a Trump appointee who had dismissed the documents case in its entirety, temporarily barred Jack Smith from releasing the results of his investigation to the public.

The president-elect and his allies have spent four years reinventing the Capitol attack — spreading conspiracy theories and weaving a tale of martyrdom to their ultimate political gain.

Four years later, the largest lingering mystery of the Capitol riot remains unsolved.