The MTA worker arrested this month for his part in the Jan. 6 storming of the US Capitol is a member of the Proud Boys, federal officials say — and is now facing more serious charges of conspiracy and civil disorder.

William Pepe, 31, of Beacon, NY, called in sick from his Metro-North job to attend the Washington, DC, rally that ended in a riot, The Post reported.

He was indicted on new charges in federal court in the District of Columbia Friday, according to the Department of Justice.

The new indictment came two weeks after Pepe’s Jan. 12 arrest on charges of illicitly entering the Capitol building.

DOJ attorneys identified Pepe and Rochester resident Dominic “Spaz” Pezzola, 43, as Proud Boys members who “engaged in a conspiracy to obstruct, influence, impede, and interfere with law enforcement officers” by removing metal crowd-control barricades and stealing Capitol Police property.

Pezzola is facing additional charges stemming from allegations that broke a window in the Capitol with a stolen police riot shield.

It was the first filing of conspiracy charges against members of the right-wing Proud Boys group, who call themselves “Western chauvinists” and are known for their violent clashes with Black Lives Matter and Antifa protesters.

Pepe has been suspended from his $73,000-a-year job as MTA officials seek his ouster.