The House select committee investigating the January 6 attack on the US Capitol on Tuesday will examine the role far-right extremist groups played in fomenting the deadly insurrection and their ties to associates of Donald Trump.

The session, the seventh in a series of public hearings to present the findings of the committee’s yearlong investigation, will focus on the connections between Trump, his allies and violent US groups such as the Proud Boys and the Oath Keepers, who stormed the US capitol in an attempt to stop the certification of Joe Biden’s electoral college victory in the 2020 election, House select committee aides told reporters on Monday.

Separately, the US Justice Department has charged members of the leadership of both groups with seditious conspiracy for their roles in instigating the assault on the Capitol.

The hearing, which will be led by Democratic members of congress Jamie Raskin of Maryland and Stephanie Murphy of Florida, will also explore the role of the QAnon conspiracy theory, the aides said.

A select committee aide said the members would focus on a meeting held on 18 December 2020, with the president and members of his legal team, including Rudy Giuliani and Sidney Powell.

At that point, there was a growing schism within Trump’s inner circle between those who believed it was time for the president to accept his electoral defeat and those who pushed even more radical actions such as seizing voting machines or appointing a special counsel to investigate the election.

Hours after the meeting, Trump sent a tweet that Murphy perceived as a “siren call” to militia groups that 6 January 2021, would be the “last stand” in a sprawling effort to overturn the results of an election he lost.

“Big protest in DC on January 6th,” Trump wrote in that December tweet. “Be there, will be wild!”

The tweet was a “pivotal moment that spurred a change of events including a pre-planning by the Proud Boys”, the aide said.

Tuesday’s hearing is the only public session the committee will hold this week. At least one more hearing is planned, likely for next week, committee aides said.

“We are going to be connecting the dots during these hearings between these groups and those who were trying – in government circles – to overturn the election,” congresswoman Zoe Lofgren, a Democrat from California and a member of the panel, said in an interview on CNN’s State of the Union show on Sunday. “We do think that this story is unfolding in a way that is very serious and quite credible.”

She added that it would be “a logical conclusion” that Trump was aware members of the violent militia groups were among those gathered at a rally on the Ellipse near the White House on the morning of January 6, when he addressed the crowd and encouraged them to march to the Capitol.