Rep. Liz Cheney, R-Wyo., vice chair of the select committee, shared snippets of what White House aides told the committee Trump said to them while the attack at the Capitol was ongoing, laying out what she called Trump's "sophisticated, seven-part plan to overturn the presidential election."

"You will hear testimony that 'The president didn’t really want to put anything out' calling off the riot or asking his supporters to leave. You will hear that President Trump was yelling and “really angry at advisers who told him he needed to do be doing something more.'

"And, aware of the rioters’ chants to 'hang Mike Pence,' the president responded with this sentiment: "Maybe our supporters have the right idea.' Mike Pence 'deserves' it," she said.

She then added, in new detail, "Not only did President Trump refuse to tell the mob to leave the Capitol, he placed no call to any element to the United States government to instruct at the Capitol be defended."

Using taped testimony from Trump officials including Attorney General Bill Barr and campaign attorney Alex Cannon, Rep. Liz Cheney, R-Wyo., argued that Trump and his team were well aware that he lost the election but still carried out a plot to stay in power.

"In our second hearing, you will see that Donald Trump and his advisers knew that he had in fact lost the election," Cheney said, explaining how the committee will lay out its case. "But despite this, President Trump engaged in a massive effort to spread false and fraudulent information to convince huge portions of the U.S. population that fraud had stolen the election from him."

In a video clip from an interview with Barr, Trump's attorney general said he "repeatedly told the president, in no uncertain terms, that I did not see evidence of fraud and -- you know, that would have affected the outcome of the election."

The committee also aired a taped interview with Trump's daughter Ivanka Trump commenting on Barr's statement that the Justice Department found no fraud sufficient to overturn the election.

"It affected my perspective," Ivanka said of Barr's assessment. "I respect Attorney General Barr, so I accepted what he was saying."

GOP Rep. Liz Cheney said Americans will learn new details about what Trump was doing before, during and after the attack at the Capitol in his effort to remain in power despite his 2020 election loss.

"Over multiple months, Donald Trump oversaw and coordinated a sophisticated seven-part plan to overturn the presidential election and prevent the transfer of presidential power," she said.

The Wyoming Republican asserted Trump told his staff during the riot that it's what people "should be doing" and that he agreed with protesters urging violence against then-Vice President Mike Pence.

After the dust settled, Cheney said, Trump continued to ignore the statements from the Department of Justice, election officials and his own staff telling him the election result was legitimate.

"President Trump summoned the mob, assembled the mob and lit the flame of this attack," she said in her opening statement.

In his opening statement, Chairman Bennie Thompson -- looking directly at the camera -- called Jan. 6 an "attempt to undermine the will of the people" and "only the beginning of what became a sprawling multistep conspiracy aimed at overturning the presidential election."

"Trump was at the center of this conspiracy, and ultimately, Donald Trump, the president of the United States, spurred a mob of domestic enemies of the Constitution to march down Capitol and subvert American democracy," he said.

Thompson said the attack on the Capitol was "the culmination of an attempted coup" and a "brazen attempt ... to overthrow the government"

"The violence was no accident," he said. "It represents President Trump's last stand, his most desperate chance to halt the transfer of power."

Three rioters convicted on federal charges for participating in the Capitol attack appeared in court just hours ahead of the prime-time event and asked for mercy before federal judges deciding their punishments.

"I made one mistake in my life and I have immediately took responsibility for it," said Michael Daughtry, a gun store owner and former police officer who pleaded guilty to a misdemeanor charge this past March. "I apologize to the court for my indiscretion. But does a person not get to make at least one mistake in their entire life?"

The sentencing hearings just blocks away from the Capitol offer a noteworthy split-screen as lawmakers and their staff are in the midst of final preparations to put their investigation's findings on full display for the American people. Click here for more.

-ABC News' Alexander Mallin