An Ohio man who claimed he was only “following presidential orders” from Donald Trump when he stormed the US Capitol has been convicted by a jury that took less than three hours to reject his novel defence for obstructing Congress from certifying Joe Biden’s presidential victory.

The federal jury on Thursday also found Dustin Byron Thompson, 38, guilty of all five of the other charges in his indictment, including stealing a coat rack from an office inside the Capitol during the riot on 6 January 2021. The maximum sentence for the obstruction count, the lone felony, would be 20 years’ imprisonment.

Jurors did not buy Thompson’s defence, in which he blamed Trump and members of the president’s inner circle for the insurrection and for his own actions.

One juror who spoke to reporters on condition of anonymity said: “Donald Trump wasn’t on trial in this case.”

The juror, a 40-year-old man, said as he left the courthouse: “Everyone agrees that Donald Trump is culpable as an overall narrative. Lots of people were there and then went home. Dustin Thompson did not.”

Thompson himself, testifying a day earlier, admitted he joined the mob’s attack and stole the coat rack and a bottle of bourbon. He said he regretted his “disgraceful” behaviour.

“I can’t believe the things that I did,” he said. “Mob mentality and group think is very real and very dangerous.”

Still, he said he believed Trump’s false claim that the election was stolen and was trying to stand up for him. “If the president is giving you almost an order to do something, I felt obligated to do that,” he said.

The US district judge Reggie Walton, who is scheduled to sentence Thompson on 20 July, described the defendant’s testimony as “totally disingenuous” and his conduct on 6 January as “reprehensible”. The judge also cast blame in Trump’s direction after the verdict was announced.

“I think our democracy is in trouble,” he said, adding that “charlatans” like Trump did not care about democracy, only about power. “And as a result of that, it’s tearing our country apart.”

Prosecutors did not ask for Thompson to be detained immediately, but Walton ordered him held and he was led away handcuffed. The judge said he believed Thompson was a flight risk and posed a danger to the public.

Thompson’s trial was the third to go before a jury among hundreds of Capitol riot cases prosecuted by the justice department. In the first two cases, jurors also convicted the defendants of all charges.

The assistant US attorney William Dreher said Thompson, a college-educated pest exterminator who lost his job during the Covid-19 pandemic, knew he was breaking the law when he joined the mob that attacked the Capitol and, in his case, looted the Senate parliamentarian’s office. The prosecutor told jurors that Thompson’s lawyer “wants you to think you have to choose between President Trump and his client.

“You don’t have to choose because this is not President Trump’s trial. This is the trial for Dustin Thompson because of what he did at the Capitol on the afternoon on Jan 6,” Dreher told jurors during his closing arguments.

The defence attorney, Samuel Shamansky, said Thompson had not avoided taking responsibility for his conduct.

“This shameful chapter in our history is all on TV,” Shamansky told jurors. But he said Thompson, unemployed and consumed by a steady diet of conspiracy theories, was vulnerable to Trump’s lies about a stolen election. He described Thompson as a “pawn” and Trump as a “gangster” who abused his power to manipulate supporters.

“The vulnerable are seduced by the strong, and that’s what happened here,” Shamansky said.

The judge had barred Thompson’s lawyer from calling Trump and ally Rudolph Giuliani as trial witnesses. But he ruled that jurors could hear recordings of speeches that Trump and Giuliani delivered on 6 January, before the riot erupted. A recording of Trump’s remarks was played.

Shamansky contended that Giuliani, the Trump adviser and former New York City mayor, incited rioters by encouraging them to engage in “trial by combat” and that Trump provoked the mob by saying: “If you don’t fight like hell, you’re not going to have a country any more.”

But Dreher told jurors that neither Trump nor Giuliani had the authority to “make legal” what Thompson did at the Capitol.

The juror who spoke on condition of anonymity said he was “laughing under my breath” when Thompson testified he took the coat rack to prevent other rioters from using it as a weapon against police.