Donald Trump's right hand man allegedly burned documents "once or twice a week" in the weeks around the attack on the US Capitol building.
It comes as the panel set up to probe the 2020 attack on the US Capitol read transcripts from explosive witness Cassidy Hutchinson and other White House staffers.
According to Hutchinson's transcripts, White House Chief of Staff Mark Meadows regularly burned documents in the period between Trump's loss at the polls and Joe Biden taking office.
She also claimed Meadows told staffers to "close hold" some Oval Office meetings, meaning some transcripts may have been omitted from official records.
Recalling a meeting in November or early December, Hutchinson alleges Meadows said: “Let’s keep some meetings close hold.
"We will talk about what that means, but for now we will keep things real tight and private so things don’t start to leak out.”
Hutchinson said she didn't remember whether anyone was given explicit information to manage conversations about the Capitol riots in the same way.
Among the documents were rumours and even conspiracies that were floating around the White House at the time.
Some were conversations about QAnon at the same time Trump was refusing to acknowledge the result and even tried to overturn it.
QAnon is a broad and nonsensical theory claiming Trump was waging a secret war against a cabal of evil elites who worship Satan and abuse children.
The theory - which is not founded on a shred of evidence - claims the conflict will result in a Messianic day of reckoning when the elites will be arrested and executed.
Hutchinson added that there “were certain things that had potentially been left off” of the diary which details the day-to-day Oval Office meetings.
She told the committee she saw Meadows burning documents in his office fire place around 12 times between December 2020 and mid-January 2021, at a rate of about once or twice a week. She confessed she didn't know what the documents were and whether they needed to be preserved by law.
At least two of the burnings happened after meetings with Pennsylvania GOP Rep. Scott Perry, who's been accused of plotting to deploy the Justice Department to overturn the 2020 election.
The shocking revelation comes after it emerged that Trump's tax returns are set to be released within the next few days.
Trump raised eyebrows when he became the first presidential candidate in recent history to refuse to release the findings when he ran for the White House in 2016.
He has since fought to keep the documents sealed but the House of Representatives' Ways and Means Committee last month obtained them after an investigation.
A spokesman has now confirmed they will be released to the public on Friday, December 30, according to an anonymous congressional aide.
They are expected to include the reality tv star's returns he filed during his years in office between 2015 and 2020.
It is understood the only redactions from the filings will be social security numbers and contact details.
Earlier today staff were seen wheeling several boxes full of documents into the hearing, possibly showing the sheer amount of information under review.
The revelation comes on the same day a report by the committee was released.
It reads: "Just like every other American, the President of the United States is obligated to pay taxes owed.
"This is a core responsibility of our common citizenship: without tax revenue, our government would cease to exist.
"Unlike many nations, we operate a largely voluntary tax compliance system, supported by oversight and auditing. That means our revenue system-- and hence our democracy--hinge on public faith that our tax laws are administered fairly and without favour.
"The public must have confidence our tax laws apply evenly and justly to all, regardless of power or position.
"The effort to provide oversight of the mandatory audit program is and always has been about ensuring that our tax laws are administered fairly and without preference.
"The Committee's investigation revealed only one mandatory audit was started under the prior Administration and the program was otherwise dormant, at best.
"For this reason, it is recommended there should be a statutory requirement for the mandatory examination of the President with disclosure of certain audit information and related returns in a timely manner."
Last month the US Supreme Court cleared the way for Trump's returns to be handed over to Congress after a three-year legal fight.
During the Trump administration the then-Treasury Secretary Steven Mnuchin withheld the tax returns from Congress arguing they were being sought by Democrats for partisan reasons.
US Presidents and party nominees have agreed to voluntarily make summaries of their taxes available to the public since Richard Nixon's time in office.
It came after media reports suggested the then president had taken large deductions in his individual returns.