A Virginia man charged over the deadly U.S. Capitol riot told an undercover FBI agent he belonged to a militia-style group that had explosives and surveilled the building a month after the insurrection, per a court filing unsealed Tuesday.

The big picture: Fi Duong, 27, who allegedly told the agent the group referred to their meetings as "Bible study," is one of more than 535 defendants arrested in nearly 50 states, the Department of Justice said in a statement marking six months since the Capitol was stormed.

• The destruction caused about $1.5 million in damage to the U.S. Capitol, according to the DOJ.

Zoom in: Duong was charged with illegally entering the Capitol, obstructing an official proceeding and disorderly conduct following his arrest Friday.

• According to an undercover agent cited in the court filing, Duong attended meetings in which there were multiple firearms and boxes of ammunition and other materials — including 50 glass bottles for molotov cocktails.
• He also discussed materials that the agent believed was "referring to making bombs using a chemical compound known as CS gas," according to the court filing.

Of note: Per the filing, an unnamed associate asked Duong during an exchange on an encrypted messaging platform on Feb. 13: "How do we feel about an intel run around the Capitol tonight?"

• Duong allegedly responded, "Fewer of them out. Posture may be lowered. Good opportunity to expose weaknesses. Poke and prod. But have a legitimate reason to go. Visit a restaurant or something."
• On March 20, Duong introduced a man he described as a member of the far-right anti-government militia the Three Percenters, which has been designated a terrorist entity in Canada.
• Several people who've identified themselves as members of the Three Percenters have been charged with conspiracy in the Jan. 6 Capitol attack.

What to watch: The FBI is still searching for riot suspects and released 11 videos on Tuesday of people seen forcefully attacking law enforcement officers that they are seeking to identify.

What they're saying: "As we mark six months since the violence at our nation’s Capitol, we continue to encourage the public to send tips to the FBI," said Steven M. D’Antuono, assistant director in charge of the FBI’s Washington Field Office, in a statement.

• "As we have seen with dozens of cases so far, the tips matter."