Donald Trump relentlessly pressured top officials at the justice department to pursue groundless claims of voter fraud in an extraordinary but ultimately unsuccessful effort to cling to power, according to testimony the House committee investigating the January 6 insurrection heard on Thursday.

Three former justice department officials who served during Trump’s final weeks in office, told the committee that the then-president was “adamant” that the election was stolen despite begin told repeatedly that none of the allegations raised about the vote count were credible.

Opening the hearing, the panel’s chair, congressman Bennie Thompson, said the hearing would show that the former president sought to “misuse the justice department as part of his plan to hold on to power”.

“Donald Trump didn’t just want the justice department to investigate,” Thompson said.

After exhausting his legal options and being rebuffed by state and local elections officials, the panel said a desperate Trump turned to the justice department to declare the election corrupt despite no evidence of mass voter fraud, the nine-member panel will seek to show in their fifth and final hearing of the month.

In one of the near-daily conversations Trump had with the agency’s leader, Rosen told the president that the Department of Justice “can’t and won’t snap his fingers and change the outcome of an election”.

In new testimony from the committee’s taped deposition with Bill Barr, the former attorney general said he thought it was important for the department to investigate – and ultimately disprove – Trump’s false claims of voter fraud.

In previous clips played by the committee, Barr said he told Trump in no uncertain terms that his claims of election fraud were “bullshit”.