Trump Under Investigation as Attorney General Calls Escalating Jan. 6 Probe 'Most Wide-Ranging' in DOJ History

Bonnie Cash-Pool/Getty Images; Jeff Bottari/Zuffa LLC Merrick Garland, Donald Trump

The U.S. Department of Justice is reportedly looking into Donald Trump's role in the attempt to overturn the 2020 presidential election.

Sources tell The Washington Post that federal prosecutors have spent hours asking witnesses detailed questions about meetings led by the former president before and around Jan. 6, 2021, when a mob of his supporters attacked the U.S. Capitol and disrupted the electoral vote count to certify Joe Biden's win.

The news that lines of inquiry are focused on Trump comes as Attorney General Merrick Garland says the Justice Department is "doing the most wide-ranging investigation in its history."

"We will hold accountable anyone who was criminally responsible for attempting to interfere with the transfer, legitimate, lawful transfer of power from one administration to the next," Garland said in an interview with NBC News' Lester Holt that aired Tuesday.

Marc Short, the former chief of staff to Vice President Mike Pence, became the highest-ranking White House official to testify before a grand jury investigating the Jan. 6, 2021, Capitol riots, he confirmed this week.

RELATED: President Biden Says 'Defeated' Trump 'Lacked the Courage' to Act as Cops Faced 'Medieval Hell' on Jan. 6

Greg Jacob, who served as Pence's counsel, also testified before the grand jury — another indication that the Justice Department's criminal investigation into Jan. 6 is intensifying.

DOJ prosecutors have reportedly acquired phone records of Trump White House officials and aides, including former chief of staff Mark Meadows, according to the Post.

Samuel Corum/Getty Rioters at the U.S. Capitol on Jan. 6, 2021

A representative for Trump did not immediately respond to PEOPLE's request for comment on the Post report about the DOJ's investigation and on portions of Garland's interview.

As the Jan. 6 House committee presented its evidence to the American people during a series of televised hearings this summer, Garland said the Justice Department has been moving "urgently" despite the appearance that its investigation is lagging behind the panel of lawmakers, who concluded that Trump allegedly played a key role in trying to subvert election results.

RELATED: Ginni Thomas Might Get a Jan. 6 Subpoena: 'Hope It Doesn't Get to That'

Garland also said questions about the Justice Department's activities are impossible to avoid.

"It is inevitable in this kind of investigation that there will be speculation about what we are doing or who we are investigating, what our theories are," Garland said. "The reason there is this speculation and uncertainty is that it's a fundamental tenet of what we do as prosecutors and investigators is to do it outside the public eye. We do that for two important reasons. One is to protect the civil liberties of people and events that we're investigating and the second is to ensure the success and the integrity of our investigation."

Andrew Harnik/AP/Bloomberg via Getty U.S. Attorney General Merrick Garland

Asked about the possibility — and dire repercussions for the country — of an indictment of a former president or a candidate for the presidency, Garland said, "We pursue justice without fear or favor."

He then reiterated an earlier point: "We intend to hold everyone, anyone who was criminally responsible for the events surrounding Jan. 6, for any attempt to interfere with the lawful transfer of power from one administration to another, accountable," he said. "That's what we do. We don't pay any attention to other issues with respect to that."

No former president has ever been charged with a crime.

RELATED: Steve Bannon Convicted by Jury on 2 Counts of Contempt of Congress After Ignoring Jan. 6 Subpoena

There are reportedly two aspects of the DOJ's inquiry that could focus on Trump, according to anonymous sources who spoke with the Post.

The first, according to the paper, is related to seditious conspiracy and conspiracy to obstruct a government proceeding, which refers to the riot at the Capitol, where lawmakers were holding the official electoral vote count on Jan. 6 for the election that Biden won.

A federal grand jury has indicted 11 individuals — including the founder and leader of far-right militia group Oath Keepers — on seditious conspiracy and other charges for their alleged involvement in the breach of the Capitol.

The second reportedly focuses on an alleged fraud connected to the use of fake electors as well as the pressure campaign Trump and his inner circle allegedly conducted to influence the Justice Department and Republican lawmakers in key states to assert or back debunked claims of election fraud.

RELATED: 'I Don't Want to Say the Election's Over': Unseen Footage of Trump on Jan. 6 Revealed at Hearing

Both aspects have been addressed by the Jan. 6 House committee.

Michael Nigro/Pacific Press/LightRocket via Getty Capitol riot on Jan. 6, 2021

Holt asked Garland in the NBC News interview whether the lawmakers on the panel are sharing "an informal roadmap" or whether he and federal prosecutors are "learning things you didn't know."

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The attorney general acknowledged that the committee's own ongoing, concurrent and "enormously wide-ranging investigation" is bound to uncover evidence before the DOJ and vice versa.

"It is inevitable that there will be things that they find before we have found them. And it's inevitable that there will be things we find that they haven't found," he said. "That's what happens when you have two wide-ranging investigations going on at the same time."