The January 6 committee investigating the attack on the Capitol may have issued its huge final report, but the wheels of the justice system in the US are grinding on and one of the most high-profile trials emerging from the insurrection is about to begin in earnest.

Jury selection began last week with the seditious conspiracy trial against ex-Proud Boys national chairman Enrique Tarrio and four others involved in the far-right, often violent militia group.

Tarrio and his co-defendants in the Washington DC federal court trial – Ethan Nordean, Zachary Rehl, Dominic Pezzola and Proud Boy organizer Joe Biggs – are charged with seditious conspiracy and other counts related to the attack that delayed congressional certification of Joe Biden’s election victory, injured dozens of police officers and is linked to multiple deaths. They have all pleaded not guilty to the charges.

A fifth man charged in this case, Charles Donohoe, pleaded guilty in April to conspiring to attack the Capitol. Under Donohoe’s plea deal, he agreed to cooperate against his co-defendants. Approximately 900 people have now been arrested in the Capitol attack, with prosecutors securing convictions against hundreds.

The start of the trial comes amid a wider reckoning with those responsible for the January 6 attack.

Several hours after jury selection started on Monday in the Proud Boys trial, the House committee probing the deadly insurrection issued some of its findings – and made a criminal referral against Trump to the US Department of Justice, recommending charges. The trial also comes several weeks after two leaders of the Oath Keepers – another far-right group – were found guilty of seditious conspiracy for their involvement in the insurrection.

Federal prosecutors allege that Nordean, Biggs, Rehl and Pezzola were among the 100 Proud Boys who convened alongside the Washington Monument at 10am on 6 January. They met around the time that Trump was addressing thousands of supporters in a park called the Ellipse.

These soon-to-be rioters in that group then made their way to the Capitol. Around 1pm, one of them broke through police, spurring the violence that would consume Capitol Hill, court documents allege.

Nordean, Rehl, Biggs and Pezzola allegedly led the mob and were among the first people to push past police. Biggs allegedly recorded a video where he observed the mob and said: “We’ve taken the Capitol,” per court documents.

Tarrio was not in Washington DC during the insurrection, as he had been arrested two days prior for allegedly vandalizing a Black Lives Matter sign at a historical Black church during a December 2020 demonstration. Prosecutors contend that Tarrio was among the leaders of this conspiracy to thwart election certification.

Several days before the riot, Tarrio posted about “revolution” on social media, prosecutors said in court papers. In an encrypted messaging group which prosecutors maintain was created by Tarrio, one member purportedly said: “Time to stack those bodies in front of Capitol Hill,” per the Associated Press.

Despite being arrested several days prior, Tarrio heralded the rioters’ attack, writing “don’t [expletive] leave” on social media and later posting “we did this…” prosecutors said.

While there appears to be extensive evidence against these men, much of which has long been in the public record, prosecutors must show more than their in-person or social media presence that day to prove seditious conspiracy.

“They’re going to have to show an agreement between two people or more, they’re going to have to show a common scheme or a common plan,” said Los Angeles criminal defense and appellate attorney Matthew Barhoma, founder of Barhoma Law.

“Showing up on January 6 at the same time doesn’t mean that a conspiracy indeed existed. They’re going to have to go a little bit beyond that to show there is a common agreement – basically a smoking gun in the sense that they intended to overthrow the government,” he added. “They’re going to have to show that they wanted to act in a common plan in furtherance of that plan to overthrow the government or to delay or hinder the United States government.”

That said, “seditious conspiracy is actually in some ways, much easier to prove than regular criminal conspiracy,” explained longtime attorney Ron Kuby, a longtime criminal defense attorney with a focus on civil rights.

“Seditious conspiracy is the only conspiracy that does not require proof of an overt act on the part of participants,” Kuby said. “Generally speaking, a conspiracy is an agreement between two or more people to do something unlawful, and in all other conspiracy cases, at least one of the participants has to take a substantial step toward that unlawful purpose.”

“Here, it’s really a sidenote, footnote, endnote and asterisk. They don’t have to prove an overt act, what they they have to prove there was an agreement to oppose the lawful authority of the United States of America by force.

“There’s a tsunami of evidence, both in terms of what was said among the participants, which the FBI has obtained and decrypted as well as what they did, which is all well-documented on video.”

Although evidence appears to abound, one possible defense strategy would be to portray the alleged plotters as buffoons. “These guys were angry knuckleheads but you know, they’re not planning to overthrow the government,” Kuby said of this possible approach.

It’s unclear whether these Proud Boys members would go along with that, even if this could help their cases.

“The natural impulse of every defense lawyer is to portray their clients in a fashion which is most likely to result in acquittal, but that’s not necessarily the way most defendants want to be portrayed,” Kuby said. “The Proud Boys may not want to be portrayed as loud-mouthed knuckleheads who were just egging each other on to say dumber and dumber things because they’re not that bright.”

Tarrio’s attorneys have contended that he didn’t tell or encourage anyone to storm the Capitol or act violently, while Nordean’s lawyer alleged that justice department prosecutors were singling him out because of his political beliefs, the AP reported.

In an email to the Guardian, Tarrio’s attorney, Nayib Hassan, said: “Mr Tarrio is looking forward to the start of the trial. We look forward to making our presentation of the evidence and acquitting Mr Tarrio of the governments allegations.”

Rehl’s lawyer reportedly wanted the judge to dismiss the indictment on First amendment grounds, claiming the charges were rooted in free speech issues. Asked for comment, Biggs’s attorney, Norm Pattis, said in an email: “We look forward to the presentation of evidence in this case. We stand by his plea of not guilty.”