(The Hill) – Prosecutors on Wednesday said a federal grand jury indicted a Pennsylvania man for threatening to kill House Jan. 6 Committee Chair Bennie Thompson (D-Miss.) in a letter sent to his Capitol office last week.

Maverick Vargo, 25, threatened President Biden, Thompson, Thompson’s family, and U.S. District Court Judge Robert Mariani in the letter, also sending what appeared to be a white powder and alluding to anthrax, prosecutors said.

Vargo, who is from Berwick, Pa., is charged with threatening the president, sending interstate communications with a threat and influencing a federal official by threat, the U.S. Attorney’s Office for the Middle District of Pennsylvania announced.

Prosecutors alleged Vargo sent the letter from the Luzerne County Correctional Facility in Wilkes-Barre, Pa., and he could now face up to 25 years in prison for the new charge.

The letter arrived at Thompson’s office in the Rayburn House Office Building days before he and his colleagues on the Jan. 6 panel held what may be their final hearing in the committee’s monthslong series to convince the public of former President Trump’s culpability for the Capitol attack.

Prosecutors said Vargas wrote to Thompson, “I’m going to kill you! I will make you feel the rest of our pain & suffering. There is nowhere or nobody who can keep you from me. I am going to kill you & those you love. I promise you that I will keep my promise until the day of my death.”

The letter also allegedly said, “you & Joe Biden soon will face death for the wrongs you’ve done to US.”

U.S. Capitol Police said last week congressional staff reported a suspicious letter to law enforcement, and the agency cleared the area near Thompson’s office as they screened it.

The agency said at the time powder was not found, despite federal prosecutors now indicating Capitol Police’s Hazardous Materials Response Team did find a white powder in the letter.

The Hill has reached out to Capitol Police for clarification.