The searing testimony and growing evidence about Donald Trump’s central role in a multi-pronged conspiracy to overturn Joe Biden’s election in 2020 presented at the House January 6 committee’s first three hearings, has increased the odds that Trump will face criminal charges, say former DoJ prosecutors and officials.

The panel’s initial hearings provided a kind of legal roadmap about Trump’s multi-faceted drives – in tandem with some top lawyers and loyalists – to thwart Biden from taking office, that should benefit justice department prosecutors in their sprawling investigations into the January 6 assault on the Capitol by a mob of Trump supporters.

Ex-justice department lawyers say new revelations at the hearings increase the likelihood that Trump will be charged with crimes involving conspiracy to obstruct an official proceeding or defrauding the United States, as he took desperate and seemingly illegal steps to undermine Biden’s election.

Trump could also potentially face fraud charges over his role in an apparently extraordinary fundraising scam – described by House panel members as the “big rip-off” – that netted some $250m for an “election defense fund” that did not exist but funneled huge sums to Trump’s Save America political action committee and Trump properties.

The panel hopes to hold six hearings on different parts of what its vice-chair, Liz Cheney, called Trump’s “sophisticated seven-part plan” to overturn the election.

Trump was told repeatedly, for instance, by top aides and cabinet officials – including ex-attorney general Bill Barr – that the election was not stolen, and that his fraud claims were “completely bullshit” and “crazy stuff” as Barr put it in a video of his scathing deposition. But Trump persisted in pushing baseless fraud claims with the backing of key allies including his ex-personal attorney Rudy Giuliani and lawyer John Eastman.

“The January 6 committee’s investigation has developed substantial, compelling evidence that Trump committed crimes, including but not limited to conspiracy to defraud the United States and obstruct official proceedings,” Michael Bromwich, a former inspector general at the DoJ told the Guardian.

Donald Ayer, a former deputy attorney general in the George HW Bush administration, told the Guardian that “the committee hearings have bolstered the need to seriously consider filing criminal charges against Trump”.

The crux of any prosecution of Trump would hinge heavily on convincing a jury that Trump knew he lost the election and acted with criminal intent to overturn the valid election results. The hearings have focused heavily on testimony that Trump fully knew he had lost and went full steam ahead to concoct schemes to stay in power.

New revelations damaging to Trump emerged on Thursday when Greg Jacob, the ex-counsel to former vice-president Mike Pence, recounted in detail how Eastman and Trump waged a high-pressure drive, publicly and privately, even as the Capitol was under attack, to prod Pence to unlawfully block Biden’s certification by Congress on January 6.

The Eastman pressure included a scheme to substitute pro-Trump fake electors from states that Biden won for electors rightfully pledged to Biden – a scheme the DoJ has been investigating for months and that now involves a grand jury focused on Eastman, Giuliani and several other lawyers and operatives.

Eastman at one point acknowledged to Jacob that he knew his push to get Pence on January 6 to reject Biden’s winning electoral college count would violate the Electoral Count Act, and that Trump, too, was told it would be illegal for Pence to block Biden’s certification.

Paul Pelletier, a former acting chief of the DoJ’s fraud section, said: “It is a target-rich environment, with many accessories both before and after the fact to be investigated.”

But experts caution any decision to charge Trump will be up to the current attorney general, Merrick Garland, who has been careful not to discuss details of his department’s January 6 investigations, which so far have led to charges against more than 800 individuals, including some Proud Boys and Oath Keepers charged with seditious conspiracy.

After the first two hearings, Garland told reporters, “I’m watching and I will be watching all the hearings,” adding that DoJ prosecutors are doing likewise.

Garland remarked in reference to possibly investigating Trump: “We’re just going to follow the facts wherever they lead … to hold all perpetrators who are criminally responsible for January 6 accountable, regardless of their level, their position, and regardless of whether they were present at the events on January 6.”

But Garland has not yet tipped his hand if Trump himself is under investigation. Despite that reticence, justice department veterans say the wealth of testimony from one-time Trump insiders and new revelations at the House hearings should spur the department to investigate and charge Trump.

Barbara McQuade, a former US attorney for eastern Michigan, said the panel’s early evidence was strong, including “video testimony of Trump insiders who told Trump that he was going to lose badly, and that with regard to claims of election fraud, there was ‘no there there’,” as Trump’s ex-chief of staff Mark Meadows acknowledged in one exchange made public at the hearings.

McQuade added that Barr’s testimony was “devastating for Trump. He and other Trump insiders who testified about their conversations with Trump established that Trump knew he had lost the election and continued to make public claims of fraud anyway. That knowledge can help establish the fraudulent intent necessary to prove criminal offenses against Trump.”

In a novel legal twist that could emerge if Trump is charged, Bromwich said: “Bizarrely, Trump’s best defense to the mountain of evidence that proves these crimes seems to be that he was incapable of forming the criminal intent necessary to convict. That he was detached from reality, in Barr’s words. But there is strong evidence that he is not crazy – but instead is crazy like a fox.

“How else to explain his attempts to pressure the Georgia secretary of state to ‘find the votes’ necessary to change the result? Or his telling DoJ officials to simply declare the election ‘corrupt’ and leave ‘the rest to me’ and Republican House allies?”

Bromwich added: “All of this shows not someone incapable of forming criminal intent, but someone who understood what the facts were and was determined not to accept them. Because he couldn’t stand to lose. That was far more important to him than honoring our institutions or the constitution.”

Former federal prosecutor Michael Zeldin said Trump could face charges over what Cheney called the “big rip-off”, which centers on the allegation that “Trump raised money from small-dollar donors after the election under false pretenses”.

Zeldin said: “Specifically, he asked for money to fight election fraud when, in fact, the money was used for other purposes. This type of conduct could violate the wire fraud statute.”

Ayer cited the importance of a justice department regulation identifying factors to consider in deciding whether to charge, and noted three of particular relevance to Trump – the nature and severity of the offence, the important deterrent effect of prosecutions, and the culpability of the individual being charged.

But it might not be all plain sailing.

Simmering tensions between the panel and the justice department have escalated over DoJ requests – rebuffed so far – to obtain 1,000 witness transcripts of committee interviews, which prosecutors say are needed for upcoming trials of Proud Boys and other cases. However, the New York Times has reported some witness transcripts could be shared next month.

Nonetheless, as Garland weighs whether to move forward with investigating and charging Trump, experts caution a prosecution of Trump would require enormous resources, given the unprecedented nature of such a high-stakes case, and the risks that a jury could end up acquitting Trump – which might only enhance his appeal to the Republican base. Yet at the same time ,the stakes for the country of not aggressively investigating Trump are also extremely high.

“No one should underestimate the gravity of deciding to criminally charge an ex-president,” said former federal prosecutor Dennis Aftergut.

For Aftergut, though, charging Trump seems imperative.

“Ultimately, the avalanche of documents and sworn testimony proving a multi-faceted criminal conspiracy to overturn the will of the people means one thing: if no one is above the law, even an ex-president who led that conspiracy must be indicted.”