The DOJ told former Trump officials they can join Congress' Jan. 6 investigations, reports say, opening up potentially damning testimony about Trump's final days in office

• Congressional committees are examining the Capitol riot and Trump's efforts to overturn the election.
• The DOJ allowed several Trump-era officials answer questions from the committees, reports say.
• The inclusion of the officials could yield new, potentially damning evidence about Trump's actions.

The Justice Department has told former Trump administration officials they can answer questions from congressional committees about the Capitol riot and the former president's efforts to overturn the 2020 election, according to reports.

A letter from the DOJ, obtained by The New York Times, Politico, and NBC News, said a select number of officials can offer "unrestricted testimony" to investigations led by the House Committee on Oversight and Reform and the Senate Judiciary Committee.

A number of former officials have already been asked by the Senate and House committees to detail the pressure they came under to investigate the legitimacy of the election, the Times said, but they were unable to take part until now.

Both committees are examining how Trump pressured officials to question the election result and how pro-Trump supporters were able to storm the Capitol on January 6.

The House Select Committee was proposed by House Speaker Nancy Pelosi following a move by Republican lawmakers to filibuster legislation to create an independent commission to investigate the January 6 riot.

The Select Committee - which is made up of seven Democrats and six Republicans - held its first hearing on Tuesday.

In it, police officers working on the Capitol that day delivered emotional testimonies about their experiences.

The move by the DOJ to permit former officials to testify suggests that new accounts of Trump's actions after the 2020 election could come to light.

Rep. Carolyn Maloney, the chairwoman of the House Committee on Oversight and Reform, told NBC News: "I expect prompt cooperation from these witnesses, and I am committed to getting to the bottom of the previous administration's attempts to subvert the Justice Department and reverse a free and fair election."

One of the issues under scrutiny is the contents of a January 6 call between Trump and House Minority Leader Kevin McCarthy. In the call McCarthy reportedly begged Trump to intervene to stop the violence, to no avail.

"The committee will want to know if there is a record of what was said," Rep. Bernie Thompson, the chairman of the House select committee, told The Guardian earlier this month.

The Senate committee has told witnesses that it is investigating "an alleged plot between then-President Donald Trump and then-acting Assistant Attorney General of the Civil Division Jeffrey Bossert Clark to use the Department of Justice to further Trump's efforts to subvert the results of the 2020 presidential election" according to NBC News.

On Tuesday, Senate Judiciary Chair Dick Durbin celebrated the DOJ's permission.

"Now that we have it, we'll proceed to interview relevant witnesses ASAP so we can get to the bottom of this plot to enlist DOJ in Donald Trump's efforts to overturn the 2020 election," he wrote.