David Dempsey had previously pleaded guilty to assaulting law enforcement with a dangerous weapon during the Jan 6 attack on the US Congressional seat in Washington.

He was sentenced to 240 months in prison, 36 months of supervised release, and ordered to pay US$2,000 by US District Judge Royce C Lamberth.

“(Dempsey’s) actions and the actions of others disrupted a joint session of the US Congress convened to ascertain and count the electoral votes related to the 2020 presidential election,” the DoJ said in a statement.

Prosecutors said that “for over one hour, defendant David Dempsey viciously assaulted and injured police officers defending the Lower West Terrace Tunnel with a variety of implements he refashioned as weapons”.

“Dempsey was one of the most violent rioters, during one of the most violent stretches of time, at the scene of the most violent confrontations at the Capitol on Jan 6, 2021,” prosecutors added in a sentencing memorandum.

According to DoJ figures, more than 1,488 individuals have been charged for crimes related to the breach of the US Capitol since Jan 6, 2021.

On Jan 6, 2021, supporters of then-US president Donald Trump violently stormed the US Congressional seat in Washington, where the Republican’s election defeat to US president Joe Biden was to be certified at the time.

A crowd incited by Trump, who held a rally to promote baseless claims of election fraud, violently entered the building, killing five people.