Three active-service US marines, all with ties to intelligence work, were arrested this week for taking part in the January 6, 2021 insurrection at the US Capitol, according to federal documents newly unsealed.

The men, all long-serving, were taken into custody on Wednesday on four charges, bringing to 12 the number of US military members charged in connection with the deadly insurrection by supporters of outgoing president Donald Trump as they tried to prevent the certification by Congress of his defeat by Joe Biden. The news was first reported by military.com.

The three were named as Micah Coomer, Joshua Abate and Dodge Dale Hellonen. According to the documents, unsealed on Thursday, they spent more than an hour together wandering around the Capitol rotunda, and at one point placed “a red Maga hat on one of the statues to take photos with it”, indicating Trump’s Make America Great Again election slogan.

Investigators noted social media posts by Coomer, including one where he stated he was “glad to be apart [sic] of history”, and a chat with another Instagram user in which he explained he was there because he was “waiting for the boogaloo”, a term popular with rightwing extremists and white supremacists to signify a race-related civil war.

Marine corps records provided to military.com show all three have been enlisted for more than four years, have good conduct medals, and that each works in “demanding jobs” tied to the intelligence community. At least one holds a “significant” security clearance.

In a statement to the outlet, a spokesperson said the service is “aware of an investigation and the allegations” and said it was “fully cooperating with appropriate authorities in support of the investigation”.

The men face misdemeanor charges including trespass, disruptive and disorderly conduct and obstructing government business.

According to the 13-page document compiled by FBI special agent Kelsey Randall of the agency’s joint terrorism taskforce, investigators “learned” of Coomer’s social media posts and, after obtaining a search warrant, identified the two others from images contained in them.

Security footage from the Capitol showed the three entering the building together through a door near the Senate chamber, and moving further inside as part of a mob of dozens of others, many wearing Trump’s signature Make America Great Again red caps.

Additional proof came from cell phone records showing the three were in the building, Randall wrote.

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