The House select committee investigating Jan. 6 will focus Tuesday on far-right extremist groups' alleged coordination with former President Donald Trump and his top aides ahead of the Capitol attack.
Committee members have said that members of the Oath Keepers and the Proud Boys, far-right groups with members who stormed the Capitol, had ties to Trump allies Roger Stone and Michael Flynn leading up to Jan. 6, 2021. Both Stone and Flynn were previously interviewed by the committee and invoked their Fifth Amendment right much of the time.
Reps. Stephanie Murphy, D-Fla., and Jamie Raskin, D-Md., will lead Tuesday's questioning, according to committee aides, who also said Monday that members would not answer specific questions about what exactly would be presented or confirm witnesses testifying due to safety concerns.
A source familiar told ABC News that Stephen Ayres of Warren, Ohio, who recently admitted to illegally entering the Capitol on Jan. 6 will testify Tuesday, as well as a former spokesman for the Oath Keepers militia group, Jason Van Tatenhove. Ayres had previously claimed that a "Civil War will ensue" if the 2020 election wasn't overturned and accused President Joe Biden, other Democrats and the mainstream media of "treason."
Tuesday's focus, per aides, will be showing how Trump allegedly grew desperate and summoned the mob to Washington, D.C., offering a "more complete understanding of the final phase of President Trump's use of radical measures to prevent the peaceful transfer of power and overturn the 2020 election."
Aides said they'd show that even though there were those in Trump's orbit who viewed the Dec. 14 Electoral College meeting as the end of the presidential election, Trump's focus shifted toward Jan. 6 to block the peaceful transfer of power.
The committee said they will look specifically at the impact of a Dec. 19, 2020, tweet sent by Trump which read, "Big protest in D.C. on January 6th. Be there, will be wild!"
Aides noted that Trump sent the tweet a little more than an hour after a meeting with Flynn and attorneys Rudy Giuliani and Sidney Powell, among others, in which seizing voting machines and appointing a special counsel to investigate the election was discussed.
Aides said on Monday the committee will also look at White House advisers who had information indicating there could be violence on Jan. 6 and more about those who would not authorize Trump's trip to the Capitol. When asked whether that meant hearing from Secret Service agents Tony Ornato, Bobby Engel or the driver of Trump's vehicle, in the wake of testimony that Trump reached for the steering wheel in an attempt to go to the Capitol, aides declined to answer.
They also said the committee would look at the involvement of members of Congress.
With the committee turning its attention to the far-right groups, prosecutors at the Justice Department are also expected to be watching Tuesday as they prosecute some of the groups' members in federal court.
The Justice Department announced an indictment last month charging the chairman of the Proud Boys, Enrique Tarrio, and four other members with seditious conspiracy -- marking the second such indictment alleging coordination leading up to the Jan. 6 attack by individuals allegedly pledging to use violence to disrupt the peaceful transition of power. All have pleaded not guilty.
Federal prosecutors had previously charged 11 members of the Oath Keepers with seditious conspiracy in January, including the group's founder, Stewart Rhodes. Three senior members of the group have pleaded guilty in the case since the indictment was returned and agreed to cooperate with Justice Department's investigation -- the remaining members have all pleaded not guilty.
In one stunning court filing last year, prosecutors alleged members of the Oath Keepers appeared to have stashed weapons at a hotel in Virginia as part of a so-called "Quick Reaction Force" they could activate if violence escalated that day.
Over the weekend, prosecutors also alleged in a court filing that at least one member of the Oath Keepers transported explosives to Washington, D.C. ahead of Jan. 6 and that at least three chapters of the group planned training camps leading up to the insurrection that focused on military-style tactics.
Asked last month whether the committee would provide witnesses who can describe actual conversations between extremist groups and Trump's inner circle, Chairman Bennie Thompson said, "Yes."
"Obviously, you'll have to go through the hearings, but we have a number of witnesses who have come forward that people have not talked to before, that will document a lot was going on in the Trump orbit while all of this was occurring," he told CNN.
Rep. Zoe Lofgren, D-Calif., who also sits on the committee, said last week after former Trump White House counsel Pat Cipollone was subpoenaed and sat for a deposition that his testimony did not contradict those of previous witnesses when he met with investigators Friday.
CNN asked the lawmaker if Americans could assume that Cipollone confirmed the testimony offered by Cassidy Hutchinson, a former top aide to Trump's chief of staff Mark Meadows, with Lofgren saying, "Not contradicting is not the same as confirming."
"He could say so and so was wrong, which he did not say. There were things that he might not be present for, or, in some cases, couldn't recall with precision. My sense was that he, as I say, he did appear voluntarily. I think he was candid with the committee. He was careful in his answers, and I believe that he was honest in his answers," she said.
While Hutchinson publicly testified that Cipollone stressed to her that Trump should not be taken to the Capitol after his rally, warning that "we're going to get charged with every crime imaginable" if he went, it was not clear if the committee asked Cipollone in his roughly eight-hour deposition about the comment.
In a video testimony aired last month, Hutchinson also said, "I recall hearing the word 'Oath Keeper' and hearing the word 'Proud Boys' closer to the planning of the January 6 rally, when Mr. Giuliani would be around."
With six public hearings down, Tuesday is the first to be held in the month of July and the only hearing of the week. Aides said they expect the committee will hold another hearing next week.
ABC News' Mike Levine contributed to this report.