Updated

A Pennsylvania man was indicted for allegedly threatening President Biden, a member of Congress and a federal judge, officials said.

Robert Maverick Vargo, 25, of Berwick, was indicted by a federal grand jury on Wednesday for allegedly mailing a letter to U.S. Rep. Bennie Thompson’s office containing threatening language, according to the Department of Justice.

Vargo is formally charged with threatening the president, sending interstate communications with a threat and influencing a federal official by threat.

Bennie Thompson with Liz Cheney

Chairman Bennie Thompson and Rep. Liz Cheney take their seats for the Select Committee to Investigate the January 6th Attack on the Capitol hearing on Oct. 13, 2022. (Bill Clark/CQ-Roll Call, Inc via Getty Images)

The letter included threats to kill Biden, Thompson and his family, and U.S. District Court Judge Robert D. Mariani. Thompson, D-Miss., is the chairman of the House Select Committee investigating the U.S. Capitol Riot on Jan. 6.

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The letter also alluded to "Anthrax." Aides initially said the letter appeared to contain white powder, but U.S. Capitol Police later told Fox News on Thursday that it was merely a stain.

"I’m going to kill you! I will make you feel the rest of our pain & suffering," prosecutors said Vargo wrote in the letter. "There is nowhere or nobody who can keep you from me."

A photo of Capitol police officers outside of the Capitol

U.S. Capitol Police officers gather on the east front plaza of the Capitol on Feb. 28, 2022. (Justin Sullivan/Getty Images)

The letter continued: "I am going to kill you & those you love. I promise you that I will keep my promise until the day of my death. You & Joe Biden soon will face death for the wrongs you’ve done to US."

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The letter was received by congressional staff inside the Rayburn House Office Building on Oct. 11. It prompted a shelter-in-place call for offices near Thompson's, although an all-clear was given later that same day.

A photo of Biden speaking

President Biden speaks in the Eisenhower Executive Office Building in Washington on Wednesday, Oct. 19, 2022. (Al Drago/Bloomberg via Getty Images)

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Investigators alleged the threatening letter was sent by Vargo from the Luzerne County Correctional Facility in Wilkes-Barre, Pennsylvania.

U.S. Capitol Police, Protective Service Bureau and the U.S. Secret Service were investigating the incident.

A photo from the House Committee on Jan 6th

A video of former President Donald Trump is displayed on a screen during a hearing of the Select Committee to Investigate the January 6th Attack on the U.S. Capitol on Thursday, Oct. 13, 2022. (Alex Wong/Getty Images/Bloomberg via Getty Images)

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If convicted, Vargo would face a total maximum penalty of 25 years in prison, supervised release and a fine.

Fox News' Chad Pergram contributed to this report.