President Trump may have lied to special counsel Robert Mueller about what he knew of his campaign's contacts with WikiLeaks, House lawyers alleged in a court filing this week.

Grand jury materials, obscured by redactions in Mueller's report, could reveal false statements under oath, the attorneys argued as they seek access for the Democrat-led House Judiciary Committee to passages that remain secret by law and, they say, may also help their investigation into Trump's communications with Ukraine.

"Not only could those materials demonstrate the President’s motives for obstructing the Special Counsel’s investigation, they also could reveal that Trump was aware of his campaign’s contacts with WikiLeaks," they wrote in a court filing to the U.S. District Court for the District of Columbia.

The six attorneys, led by House General Counsel Douglas Letter, refer to redacted text in Mueller's report cited in a passage about former Trump campaign manager Paul Manafort "having 'recalled that Trump' seemingly asked to be kept 'updated' about WikiLeaks’s plans ... and Manafort’s deputy having indicated that Trump had some knowledge of those plans."

"The text ... and any underlying evidence to which it may point are critical to the Committee’s investigation," the attorneys wrote.

The lawyers said the grand jury materials they sought “have direct bearing on whether the President was untruthful, and further obstructed the Special Counsel’s investigation, when in providing written responses to the Special Counsel’s questions he denied being aware of any communications between his campaign and WikiLeaks.” The Democrats want access not just to the grand jury information redacted in the report but also grand jury information that didn’t make its way into the report.

It is the latest salvo in a legal back-and-forth in which the Justice Department has said multiple investigations and judicial proceedings that grew out of Mueller’s investigation are still ongoing and stated that “the need to ensure that all charged defendants receive fair trials and the need to preserve the integrity of ongoing investigations far outweigh the [Judiciary] Committee’s asserted need for the requested materials.” The DOJ also argued congressional impeachment proceedings are not official “judicial proceedings,” and so the demand from Democrats for grand jury material should be rejected.

Democrats countered that the text of the Constitution states Senate impeachment proceedings are trials and added that “the Executive Branch has never before objected to the disclosure of grand jury material to the House for an impeachment inquiry.” Besides shedding light on the Trump campaign’s alleged outreach to WikiLeaks, Democrats said the grand jury material could also help them understand the full scope of the illicit activities undertaken by former Trump campaign chairman Paul Manafort in Ukraine and elsewhere, specifically citing the “black ledger” that purportedly shows millions of dollars in payments made by pro-Kremlin former Ukrainian President Viktor Yanukovych to Manafort.

Special counsel Robert Mueller's report cited substantial evidence showing Russian actors hacked Democratic email accounts and disseminated the thousands of stolen emails via WikiLeaks in 2016. Mueller said Russia's Main Intelligence Directorate of the General Staff, or GRU, stole these emails and then distributed them through two GRU-operated fronts: the DCLeaks and Guccifer 2.0 websites. Mueller stated that “the GRU units transferred many of the documents they stole from the DNC and the chairman of the Clinton Campaign to WikiLeaks.” The DCLeaks and Guccifer 2.0 personas were the Russian conduits for communication with WikiLeaks, according to Mueller.

Mueller’s report noted that “the Trump campaign showed interest in WikiLeaks’s releases of hacked materials throughout the summer and fall of 2016.” The sections related to WikiLeaks are heavily redacted, sometime for pages at a time, with notations stating that information is being withheld because it is grand jury material or because it could harm an ongoing investigation. The portions that are unredacted note that Manafort, former deputy campaign chairman Rick Gates, former Trump lawyer Michael Cohen, Donald Trump Jr., and others all had interest in the WikiLeaks disclosures, but many of their specific actions and comments remain concealed in the report.

After a 22-month investigation, Mueller's team did not find sufficient evidence to establish criminal conspiracy took place between the Trump campaign and the Russian government. He also declined to make a determination about whether Trump may have obstructed justice, but did lay out 10 instances of possible obstruction that Democrats viewed as a road map to continue investigating and possibly seek impeachment.

Before the report's release, Attorney General William Barr and then-Deputy Attorney General Rod Rosenstein released a summary of the Mueller investigation's principal conclusions, which said the evidence was “not sufficient to establish that the president committed an obstruction-of-justice offense.”