A member of the far-right Proud Boys pleaded guilty on Thursday to a charge of seditious conspiracy over his role in the January 6, 2021, attack on the US Capitol, making him the first member of the group to do so.
Jeremy Bertino of North Carolina could potentially become a key witness against five other members of the group, including former Proud Boys chairman Enrique Tarrio, who are due to stand trial beginning in December on charges including seditious conspiracy.
Prosecutors said on Thursday that Bertino was not present at the Capitol on January 6, 2021, but was involved in private chats with other members who openly discussed the possibility of storming the Capitol.
They said Bertino participated in chats with other members about an alleged plot to stop Congress from certifying Democrat Joe Biden's electoral win because they felt the election had been stolen from Republican then-president Donald Trump.
On his own social media account, he posted messages such as: “DO NOT GO HOME. WE ARE ON THE CUSP OF SAVING THE CONSTITUTION.”
Bertino's guilty plea comes as the first seditious conspiracy trial of Trump supporters charged with organising the Capitol assault begins.
That trial involves five associates of the far-right group the Oath Keepers, including founder Stewart Rhodes.
As part of his plea deal, Bertino must agree to give evidence before a grand jury or at trial if requested by federal prosecutors.
He could face a prison sentence of up to five years and three months and a fine of up to $200,000, officials said at an online hearing.
However, prosecutors said that if Bertino co-operates, they may seek a reduction in his sentence and he may be eligible for a witness security programme.
Seditious conspiracy is a Civil War-era statute defined as two or more people plotting “to overthrow, put down or to destroy by force the government of the United States” that is rarely prosecuted.
In addition to Bertino, three members of the Oath Keepers — Joshua James, Brian Ulrich and William Todd Wilson — pleaded guilty this year to engaging in seditious conspiracy in connection with the attack.
They are awaiting sentencing and could potentially be called as witnesses against Mr Rhodes and other accused.
The storming of the Capitol failed to stop the congressional certification of Mr Biden's electoral victory and resulted in Mr Trump's second impeachment.
Five people died during and shortly after the riot, and about 140 police officers were injured.