A crowd gathers outside the US Capitol on January 6, 2021 in Washington, DC.
CNN  — 

A member of the Oath Keepers has cut a plea deal with prosecutors and is testifying secretly against others in the right-wing group, according to a criminal case unsealed Wednesday in Washington, DC.

The newly public case is the latest known move by the Justice Department to prosecute the extremist group for planning the January 6 attack on Congress.

Mark Grods, a 54-year-old Alabaman, pleaded guilty to two charges – conspiracy and obstruction of Congress’ certification of the Electoral College votes – at a court hearing on Wednesday.

Though the Justice Department identified in court that Grods played a minor role in the conspiracy, he appears to have been witness to some of the central moves made by the Oath Keepers as they arranged guns around Washington, DC, and participated in the insurrection.

He admitted to taking part in paramilitary training efforts before January 6 and recruiting people to come to DC and join together for the siege. Grods and others brought firearms, combat outfits, helmets and radio equipment for the siege, according to the charging document.

Grods also admitted to allegations that he stormed the Capitol with others, taking part in the military-style “stack” formation used by the Oath Keepers to cut through the crowd, while carrying a “large stick,” according to his court record.

Grods’ plea deal was filed in court confidentially on Monday and made public Wednesday morning. The secrecy would “ensure the defendant’s safety while he cooperates pursuant to his plea agreement and testifies before the grand jury,” a court filing from the Justice Department said.

He and his lawyer declined to comment about his case on Wednesday. In court, when asked if he intentionally was trying to obstruct Congress on January 6, he responded: “Yes, your honor.”

Grods stayed at the Mayflower Hotel while in DC, though he had handed off guns to another person to keep at a hotel in Virginia, his charging document says.

Prosecutors have accused several Oath Keeper defendants of coordinating what they called a “Quick Reaction Force” – by storing an arsenal across the river from DC in Virginia that could be brought in as backup if needed during the pro-Trump push to block Congress’s certification of the 2020 election results.

Grods also rode in a pair of golf carts to get to the Capitol quickly, swerving around law enforcement, during the siege, his charging document says.

Grods was not charged previously in the sprawling conspiracy case against the Oath Keepers prosecutors have aggressively pursued.

In recent weeks, the Justice Department flipped one of the conspiracy co-defendants against the Oath Keepers in a plea deal secured last week – a major step forward in the 16-defendant case – and also gained a cooperator who had long-term ties to the organization and attended the January 6 riot.

Other Oath Keepers charged in the Capitol riot cases have pleaded not guilty.

Following Grods’ hearing Wednesday, he was released and told he can’t be in touch with others in the Oath Keepers’ case, as he will likely continue to cooperate against them. When he’s ultimately sentenced, he could face more than 4 or 5 years in prison. He has also agreed to pay for some of the damage to the US Capitol.

This has been updated with additional details from the hearing.