“BOOM! Down goes another accused OathKeeper,” Scott MacFarlane, an NBC Washington reporter covering the investigation, wrote on Twitter. “Big early wins for US Justice Dept.”
Prosecutors say the defendant, Caleb Berry, helped plan and organise the insurrection, and was among the mob that forced its way into the building. He has been charged with conspiracy and obstruction of an official proceeding, and reportedly plans to plead guilty to both counts on Tuesday.
It was not immediately clear whether Mr Berry would cooperate with authorities.
According to the Southern Poverty Law Center, the Oath Keepers are “one of the largest radical anti-government groups in the US today,” whose members include tens of thousands of military veterans and former and current law enforcement officials.
“While it claims only to be defending the Constitution, the entire organisation is based on a set of baseless conspiracy theories,” SPLC says.
Close to 20 Oath Keepers have been charged in connection to the Capitol riot, and three of them – Jon Schaffer, Graydon Young, and Mark Grods – have already pleaded guilty and agreed to cooperate with investigators.
In the charging document, prosecutors clearly linked Mr Berry to the paramilitary group, which they say played a large role in organising the attack.
“On January 6, 2021, BERRY and others known and unknown equipped themselves with communication devices and reinforced vests, helmets, and goggles, and donned clothing and patches with the Oath Keepers name, logo, and insignia,” the indictment says.
The document also accuses Mr Berry of “coordinating in advance with others, including members of the Oath Keepers,” attending planning and training sessions, recruiting others to take part in the assault, bringing firearms and other paramilitary equipment to Washington, and “moving together in a military ‘stack’ formation” as they advanced toward the Capitol.
In doing so, the indictment says, Mr Berry “did knowingly combine, conspire, confederate, and agree with others known and unknown to commit an offense against the United States.”
Mr Berry’s plea hearing in the District Court of Washington, DC, is scheduled for 3pm on Tuesday afternoon.