Congress returns from a two-week recess this week with promises of two more hearings by the committee investigating the January 6 riots at the Capitol, one focusing on extremist groups involved in the fracas and a second, prime-time hearing focusing on President Trump’s activities on the day.

The two hearings this week will focus on the connections — if any — between Mr. Trump, his staff and two extremist groups, the Proud Boys and the Oath Keepers, who are said to have been behind much of the violence at the Capitol. Specifically, committee members are expected to lay out a case that Mr. Trump encouraged the groups.

“The focus on this next hearing will be on the domestic violent extremists, as well as members of Congress — people that the president called in to assist him in this pressure campaign,” Representative Stephanie Murphy said on “Meet the Press” Sunday morning in regard to Tuesday’s hearing. 

“We will lay out the body of evidence that we have that talks about how the President’s tweets on the wee hours of December 19 of ‘Be there, Be wild’ was a siren call to these folks,” Ms. Murphy said.

In court filings made public late Friday, the Department of Justice alleged that the Oath Keepers, an anti-federal government militia, held military training prior to January 6 and stocked up on firearms and explosives in the Washington, D.C. area. No such weapons were fired by protesters, though pipe bombs were discovered outside both the Republican and Democratic headquarters in the capital. 

The details were included in a list of evidence prosecutors intend to use during a September trial of nine Oath Keepers charged with seditious conspiracy. Authorities also said they found a “death list” with the names of Georgia election officials that members of the group believe hijacked the vote in that state on behalf of President Biden.

Tuesday’s hearings will likely build on testimony provided by the previous hearing’s star witness, former White House aide Cassidy Hutchinson, and will feature recorded testimony from former White House counsel Pasquale “Pat” Cipollone, who spent eight hours behind closed doors with members of the committee on Friday.

Ms. Hutchinson did not allege any collaboration between the Oath Keepers, Proud Boys, and the White House in her testimony, but she painted a picture of indifference to reports of such groups and the havoc they might wreak.

“I recall hearing the word Oath Keeper and hearing the word Proud Boys closer to the planning of the January 6th rally when Mr. Giuliani would be around,” she told the committee in taped testimony. 

Once the White House was made aware of the “potential for violence,” the White House Chief of Staff, Mark Meadows, “did not act on those concerns,” Ms. Hutchinson said.

Mr. Cipollone, she told the committee, had privately expressed concern about January 6, calling a presidential trip to the Capitol “a terrible idea.”

In a statement, Timothy Mulvey, a spokesman for the January 6 committee, said Mr. Cipollone provided “highly relevant new information” in his “critical testimony on nearly every major topic in its investigation” during his testimony Friday.

Mr. Cipollone’s testimony is sealed until a committee vote. He will not testify live on Tuesday, but recorded and transcribed excerpts from his Friday testimony could be featured following the vote. 

Live witnesses and testimony have not yet been announced.

Another member of the committee, Representative Adam Kinzinger, an Illinois Republican, said in an appearance on ABC’s “This Week” on Sunday that the Thursday evening hearing will focus on Mr. Trump’s activities on the day. It will be the second primetime hearing held by the committee.

“We want to show the American people what was the president doing during that time,” Mr. Kinzinger said. “The rest of the country knew that there was an insurrection. The president obviously had to have known there was an insurrection. So where was he? What was he doing? It’s a very important hearing. Pay attention. Because I think it goes to the heart of what is the oath of a leader.”

Committee members also expect former Trump advisor Stephen Bannon to testify before the committee in the coming weeks. Mr. Trump has reportedly waived his executive privilege, and Mr. Bannon’s lawyer has been in communication with the committee.

Mr. Bannon’s lawyer told the January 6 Committee chairman, Bennie Thompson, a Democrat from Mississippi, in a letter late Saturday that his client would like to testify in light of Mr. Trump’s waiver. He noted that Mr. Bannon would prefer to testify in a public hearing — like Ms. Hutchinson, rather than in private like Mr. Cipollone. 

“Mr. Bannon has not had a change of posture or of heart,” his lawyer, Robert Costello. “While Mr. Bannon has been steadfast in his convictions, circumstances have now changed… Mr. Bannon is willing to, and indeed prefers, to testify at your public hearing.” 

Mr. Bannon’s testimony would add to the grand tally of more than 1,000 persons to whom the committee had spoken to, according to Representative Jamie Raskin.