Members of the House Select Committee investigating the January 6 attack on the US Capitol listen during the first hearing Thursday, June 9 in Washington, DC. (Aaron Schwartz/Xinhua via Getty Images)

The expected testimony of former President Donald Trump’s campaign manager Bill Stepien before the Jan. 6 House committee was unexpectedly turned on its head Monday when Stepien said he was unable to appear due to a family emergency.

The development was “disruptive” to Monday’s hearing, a source familiar with the committee’s plans said, but the panel is prepared for such eventualities and has video clips of Stepien’s previous testimonies.

Monday’s hearing, the House of Representatives’ second Jan. 6 hearing this month, will focus on Trump’s lies about the 2020 election.

Representatives Committee aides said the hearing would look at how Trump picked up false allegations of cheating in the 2020 election and how he decided to declare victory in the hours after the election, though he was told the numbers didn’t back it up.

Aides said the hearing would show how Trump’s team pursued legal challenges in court and lost those cases, and that Trump then chose to ignore the will of the courts and continued trying to overturn the election.

The hearing will also seek to connect Trump’s lies about the election to the Jan. 6, 2021 US Capitol violence, aides said, including the way rioters repeated the former president’s baseless claims that the election was stolen.

Among those expected to testify is Former Fox digital politics editor Chris Stirewalt’s decision to call Arizona for Joe Biden on election night infuriated the Trump campaign — and conservative Fox anchors.

A second group of witnesses testifying Monday includes former US Attorney for the Northern District of Georgia BJay Pak, who was pressured into accepting Trump’s fraud allegations and has resigned; former Philadelphia City Commissioner Al Schmidt, who debunked false allegations of voter fraud in Philadelphia; and Conservative Election Attorney Ben Ginsberg, who is expected to speak about the failed court cases being pursued by Trump’s team.

Stepien was perhaps the most intriguing witness as a key member of Trump’s team during the 2020 campaign. He was due to appear under subpoena, he told CNN on Sunday.

Here are the key things to keep in mind during Monday’s hearing:

Debunking Trump’s fraud allegations

The hearing is the second of seven the January 6 Committee has scheduled for this month as it sets out a case that puts Trump at the center of efforts to end the 2020 election and the violence that unfolded on January 6 in the Capitol unfolded to overthrow.

Monday’s hearing is focused on voter fraud, and the committee is trying to demonstrate to the public that Trump’s claims that the 2020 election were stolen — those made by a significant constituency of Republicans, including many GOP candidates who are campaigning this year apply for office – have been accepted are wrong.

More video of testimonies

Stepien’s role at the hearing – and what he has to say about voter fraud – should make for Monday’s most notable moments. But aides said they also plan to play more videos of behind-closed-door interviews they’ve conducted with many in Trump’s orbit.

Those videos proved crucial to the committee’s opening hearing on Thursday, which previewed how the panel was told many of those close to Trump knew his allegations of voter fraud were false.

A more traditional listen

The first hearing included two witnesses — a Capitol Police officer and a documentary filmmaker who was with extremist groups on January 6 — but their testimony came after a lengthy presentation by committee chairs Benny Thompson and Cheney summarizing the panel’s findings, as well as one long video showing new footage of the violent attack on the Capitol.

Aides said Monday’s hearing would be a return to a more traditional congressional hearing, where the rest of the committee would ask questions and present two groups of witnesses.

While Thompson will chair the hearings, Rep. Zoe Lofgren, a California Democrat, will play a key role in Monday’s hearing focused on voter fraud, aides said.

It’s a pattern likely to continue among the rest of the committee members in future hearings examining how Trump and his allies have attempted to pressure the Justice Department, the state legislature and his former Vice President Mike Pence to help overturn the election, as well as what the committee says is Trump’s role in instigating the Capitol riot and his failure to respond as the violence unfolded.

CNN’s Katelyn Polantz contributed to this report.

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