Special Councel Robert Mueller walks past the White House after attending services at St. John’s Episcopal Church in Washington on March 24, 2019. Mueller closed his long and contentious Russia investigation Sunday with no new charges, ending the probe that has cast a dark shadow over Donald Trump’s presidency. (AP Photo/Cliff Owen)

WASHINGTON (CN) – The chairmen of six committees in the House of Representative have demanded that Attorney General William Barr hand over by April 2 the entirety of Special Counsel Robert Mueller’s report, as well as any underlying evidence related to the investigation.

In the joint letter issued Monday night, chairmen of the House Committees for Intelligence, Ways and Means, Financial Services, Judiciary, Oversight, and Foreign Affairs said the 4-page summary Barr issued on Mueller’s two-year-long investigation is “not sufficient for Congress.”

“Your March 24 letter concerning Special Counsel Mueller’s report leaves open many questions concerning the conduct of the President and his closest advisors, as well as that of the Russian government during the 2016 presidential election,” the 3-page letter states.

In his summary of Mueller’s report, Barr wrote that, despite “multiple offers from Russian-affiliated individuals to assist the Trump campaign,” no evidence was ultimately found by Mueller proving the campaign conspired with the Kremlin in order to influence the 2016 election.

The special counsel also opted not to take a position on whether the president obstructed justice by trying to disrupt the investigation.

In his summary, Barr quoted Mueller: “While this report does not conclude that the President committed a crime, it also does not exonerate him.”

But lawmakers want Mueller’s findings in a “complete and un-redacted” form.

In their letter Monday, the committees also beseeched Barr to “begin the process of consultation” around the report’s release with members of Congress so that any legal limitations potentially impacting the publication, could be discussed and parameters mutually established.

The request by the Democratic chairmen – including Reps. Jerrold Nadler and Eliot Engel of New York, Reps. Adam Schiff and Maxine Waters of California, Rep. Elijah Cummings of Maryland, and Rep. Richard Neal of Massachusetts – was largely expected.

Democrats control the House and, with the authority to subpoena, the committee heads have long signaled they would pursue transparency once the Mueller probe wrapped up.

During a scrum with reporters Monday night, Cummings offered his thoughts on what Mueller intended with his report.

“I believe that what Mueller was saying by not making a finding with regard to obstruction, was that he wanted Congress to take a look at it and we make the decision,” said Cummings, who chairs the House Committee on Oversight and Reform.

Though Cummings and other committee heads have vowed to continue oversight, at least one long-awaited Trump-campaign-connected hearing has been postponed.

Felix Sater, the Russian-mafia tied businessman and fixer for the aborted Trump Tower Project in Moscow, was scheduled to testify publicly about his knowledge of the deal before the House Intelligence Committee this Wednesday.

But the hearing was abruptly canceled Monday afternoon, the same day Sater was slapped with a federal lawsuit in New York. The complaint, brought by BTA Bank and the City of Almaty in Kazakhstan, accuses Sater of money laundering and coordinating a plot to use those stolen funds to build Trump Tower in Moscow.

A spokesperson for the committee did not specify why the hearing was nixed.