Hours before the deadly attack on the US Capitol this year, Donald Trump made several calls from the White House to top lieutenants at the Willard hotel in Washington and talked about ways to stop the certification of Joe Biden’s election win from taking place on 6 January.

The former president first told the lieutenants his vice-president, Mike Pence, was reluctant to go along with the plan to commandeer his largely ceremonial role at the joint session of Congress in a way that would allow Trump to retain the presidency for a second term.

But as Trump relayed to them the situation with Pence, he pressed his lieutenants about how to stop Biden’s certification from taking place on 6 January, and delay the certification process to get alternate slates of electors for Trump sent to Congress.

The former president’s remarks came as part of strategy discussions he had from the White House with the lieutenants at the Willard – a team led by Trump lawyers Rudy Giuliani, John Eastman, Boris Epshteyn and Trump strategist Steve Bannon – about delaying the certification.

Multiple sources, speaking to the Guardian on the condition of anonymity, described Trump’s involvement in the effort to subvert the results of the 2020 election.

Trump’s remarks reveal a direct line from the White House and the command center at the Willard. The conversations also show Trump’s thoughts appear to be in line with the motivations of the pro-Trump mob that carried out the Capitol attack and halted Biden’s certification, until it was later ratified by Congress.

The former president’s call to the Willard hotel about stopping Biden’s certification is increasingly a central focus of the House select committee’s investigation into the Capitol attack, as it raises the specter of a possible connection between Trump and the insurrection.

Several Trump lawyers at the Willard that night deny Trump sought to stop the certification of Biden’s election win. They say they only considered delaying Biden’s certification at the request of state legislators because of voter fraud.

The former president made several calls to the lieutenants at the Willard the night before 6 January. He phoned the lawyers and the non-lawyers separately, as Giuliani did not want non-lawyers to participate on legal calls and jeopardise attorney-client privilege.

Trump’s call to the lieutenants came a day after Eastman, a late addition to the Trump legal team, outlined at a 4 January meeting at the White House how he thought Pence could usurp his role in order to stop Biden’s certification from happening at the joint session.

At the meeting, which was held in the Oval Office and attended by Trump, Pence, Pence’s chief of staff Marc Short and his legal counsel Greg Jacob, Eastman presented a memo that detailed how Pence could insert himself into the certification and delay the process.

The memo outlined several ways for Pence to commandeer his role at the joint session, including throwing the election to the House, or adjourning the session to give states time to send slates of electors for Trump on the basis of election fraud – Eastman’s preference.

Then– acting attorney general Jeff Rosen and his predecessor, Bill Barr, who had both been appointed by Trump, had already determined there was no evidence of fraud sufficient to change the outcome of the 2020 election.

Eastman told the Guardian last month that the memo only presented scenarios and was not intended as advice. “The advice I gave the vice-president very explicitly was that I did not think he had the authority simply to declare which electors to count,” Eastman said.

Trump seized on the memo – first reported by Washington Post journalists Bob Woodward and Robert Costa in their book Peril – and pushed Pence to adopt the schemes, which some of the other lieutenants at the Willard later told Trump were legitimate ways to flip the election.

But Pence resisted Trump’s entreaties, and told him in the Oval Office the next day that Trump should count him out of whatever plans he had to subvert the results of the 2020 election at the joint session, because he did not intend to take part.

Trump was furious at Pence for refusing to do him a final favor when, in the critical moment underpinning the effort to reinstall Trump as president, he phoned lieutenants at the Willard sometime between the late evening on 5 January and the early hours of 6 January.

From the White House, Trump made several calls to lieutenants, including Giuliani, Eastman, Epshteyn and Bannon, who were huddled in suites complete with espresso machines and Cokes in a mini-fridge in the north-west corner of the hotel.

On the calls, the former president first recounted what had transpired in the Oval Office meeting with Pence, informing Bannon and the lawyers at the Willard that his vice-president appeared ready to abandon him at the joint session in several hours’ time.

“He’s arrogant,” Trump, for instance, told Bannon of Pence – his own way of communicating that Pence was unlikely to play ball – in an exchange reported in Peril and confirmed by the Guardian.

But on at least one of those calls, Trump also sought from the lawyers at the Willard ways to stop the joint session to ensure Biden would not be certified as president on 6 January, as part of a wider discussion about buying time to get states to send Trump electors.

The fallback that Trump and his lieutenants appeared to settle on was to cajole Republican members of Congress to raise enough objections so that even without Pence adjourning the joint session, the certification process would be delayed for states to send Trump slates.

It was not clear whether Trump discussed on the call about the prospect of stopping Biden’s certification by any means if Pence refused to insert himself into the process, but the former president is said to have enjoyed watching the insurrection unfold from the dining room.

But the fact that Trump considered ways to stop the joint session may help to explain why he was so reluctant to call off the rioters and why Republican senator Ben Sasse told conservative talk show host Hugh Hewitt that he heard Trump seemed “delighted” about the attack.

The lead Trump lawyer at the Willard, Giuliani, appearing to follow that fallback plan, called at least one Republican senator later that same evening, asking him to help keep Congress adjourned and stall the joint session beyond 6 January.

In a voicemail recorded at about 7pm on 6 January, and reported by the Dispatch, Giuliani implored Republican senator Tommy Tuberville to object to 10 states Biden won once Congress reconvened at 8pm, a process that would have concluded 15 hours later, close to 7 January.

“The only strategy we can follow is to object to numerous states and raise issues so that we get ourselves into tomorrow – ideally until the end of tomorrow,” Giuliani said.

A spokesperson for Trump did not respond to requests for comment on this account of Trump’s call. Giuliani did not respond to a request for comment. Eastman, Epshteyn and Bannon declined to comment.

Trump made several calls the day before the Capitol attack from both the White House residence, his preferred place to work, as well as the West Wing, but it was not certain from which location he phoned his top lieutenants at the Willard.

The White House residence and its Yellow Oval Room – a Trump favorite – is significant since communications there, including from a desk phone, are not automatically memorialized in records sent to the National Archives after the end of an administration.

But even if Trump called his lieutenants from the West Wing, the select committee may not be able to fully uncover the extent of his involvement in the events of 6 January, unless House investigators secure testimony from individuals with knowledge of the calls.

That difficulty arises since calls from the White House are not necessarily recorded, and call detail records that the select committee is suing to pry free from the National Archives over Trump’s objections about executive privilege, only show the destination of the calls.

House select committee investigators last week opened a new line of inquiry into activities at the Willard hotel, just across the street from the White House, issuing subpoenas to Eastman and former New York police commissioner Bernard Kerik, an assistant to Giuliani.

The chairman of the select committee, Bennie Thompson, said in a statement that the panel was pursuing the Trump officials at the Willard to uncover “every detail about their efforts to overturn the election, including who they were talking to in the White House and in Congress”.