During the course of its landmark summer of hearings, the House select committee investigating the deadly insurrection at the US Capitol has sought to show that Donald Trump was at the center of a multi-layer conspiracy to seize a second term in office, accusing him of having “summoned the mob, assembled the mob and lit the flame of this attack”.

Then, for 187 minutes on 6 January, the president let the firestorm he ignited burn, the panel argued in a gripping capstone presentation on Thursday.

In its final midsummer hearing, one of its most dramatic of the series of eight, the panel argued that Trump betrayed his oath of office and was derelict in his duty when he refused to condemn the violence as rioters carrying poles, bear spray and the banners of his campaign, led a bloody assault on the US Capitol.

The primetime session recounted in harrowing, minute-by-minute detail the siege of the Capitol, while simultaneously laying out the actions Trump did – but mostly deliberately did not – take during those excruciating hours when “lives and our democracy hung in the balance,” as Congresswoman Elaine Luria, a Democrat of Virginia and a member of the committee, described it on Thursday.

Amid the chaos at the Capitol, Trump was idle in the White House, watching it all unfold on a television tuned to Fox News. Even 24 hours later, Trump refused to say the election was over.

Trump’s abdication of leadership on 6 January was a “stain on our history”, Congressman Adam Kinzinger, Republican of Illinois and a committee member, said Thursday.

But were his actions illegal? It’s a question at the heart of the committee’s yearlong inquiry.

Over the course of the public hearings, the panel has sought to lay out the case that Trump orchestrated a multilayered plot to seize another term in office despite being told repeatedly and in no uncertain terms that his myth of a stolen election was baseless.

Culling from hundreds of thousands of documents and hundreds of interviews, the committee showed that Trump, having been turned back by the courts at every level, became increasingly desperate in his bid to overturn the results of an election his own attorney general deemed free and fair.

The panel has sought to offer a full public accounting of the events of 6 January for the American people and for the historical record.

Its work, however, is not done.

The vice-chair, Liz Cheney, a Republican of Wyoming, said that the committee will spend August “pursuing and merging information”, which continues to come in, before reconvening for more hearings in September.

While the committee originally set a September deadline for releasing a final report on their investigation, lawmakers now say it will only release a preliminary report by then, and a full report by the end of the year. The committee must release a full report before it disbands, which it is set to do with the start of a new Congress in early January.

The committee’s report is already getting treatment similar to other major investigations such as Watergate and 9/11. Multiple publishers, including Hachette and MacMillan, have books coming out in September related to the committee’s findings.

But already, the committee has presented evidence that lawmakers and aides have suggested could be used as a foundation for bringing a criminal case against the former president. Among the possible charges that have been discussed are conspiracy to defraud the American people and obstructing an official proceeding of Congress. The committee has also raised the prospect of witness tampering, announcing at its last hearing that Trump had attempted to contact a witness cooperating with its investigation.

“The facts are clear and unambiguous,” Thompson said on Thursday.

The Justice Department is pursuing a separate investigation into the breach of the Capitol.

A federal judge has said Trump “more likely than not” committed federal crimes in his efforts to delay or disrupt the congressional count of electoral college votes on January 6.

But legal experts are divided over whether the evidence shown during the hearings is enough to charge Trump. No former president has ever been prosecuted by the justice department. And in this era of polarization, there are risks that both charging Trump – or declining to do so – could further undermine Americans faith in their system of justice.

The attorney general, Merrick Garland, under immense pressure by Democrats to act, has not said whether he is considering a case against Trump.

“No person is above the law in this country,” he said Wednesday. “I can’t say it any more clearly than that.”

Trump has dismissed the panel’s inquiry as politically motivated and a witch hunt.

Perhaps the panel’s most urgent work is to show Americans that the “forces Donald Trump ignited that day have not gone away”, Kinzinger said. “The militant, intolerant ideologies. The militias. The alienation and the disaffection. The weird fantasies and disinformation. They’re all still out there, ready to go.”

Millions of voters still believe the conspiracy that Trump was the rightful winner of the 2020 election. It has galvanized a new wave of Republican candidates, who openly embrace the lie that the 2020 election was illegitimate. Many are now their party’s nominee for critical positions such as governor and secretary of state.

Trump was impeached for actions on 6 January, but the Senate acquitted and never attempted to bar him from holding future public office. Cheney suggested Thursday that if what was known now about Trump’s role in the tangled, brazen plot to keep him in office, the Senate may have voted differently. But the opportunity for political accountability is not presently available – Trump is out of office, for now.

That is why many, including members of the committee, believe Trump must face consequences for his actions.

“If there’s no accountability for January 6, for every part of this scheme, I fear we will not overcome the ongoing threat to our democracy,” Thompson warned. “There must be stiff consequences for those responsible.”

• This article was amended on 22 July 2022. Liz Cheney is a Republican member for Wyoming, not Wisconsin as an earlier version said.