(NewsNation) — A Utah man was shot to death by FBI agents Wednesday morning during a raid investigating threats to harm President Joe Biden.

The FBI’s Salt Lake City office said in a statement that the agency is reviewing the shooting, which happened around 6:15 a.m. in Provo.

Agents were attempting to serve arrest and search warrants at a residence when the shooting happened, the FBI said.

According to charging documents, Craig Robertson, the man who was killed, threatened to assault or murder Biden in a social media post made on or around Monday Aug. 7.

NewsNation local affiliate KTVX reported that Biden was in Utah to sign a national monument designation for the Greater Grand Canyon on Tuesday.

“I HEAR BIDEN IS COMING TO UTAH. DIGGING OUT MY OLD GHILLE SUIT AND CLEANING THE DUST OFF THE M24 SNIPER RIFLE,” Robertson allegedly wrote. “WELCOME, BUFFOON-IN-CHIEF!”

An official told ABC News the threats had been deemed credible. Not only did Robertson make threatening posts, the official said to ABC, but he also made plans to take physical action.

In a statement to NewsNation, the Salt Lake FBI said the agency takes all shooting incidents involving agents or task force members seriously.

“In accordance with FBI policy, the shooting incident is under review by the FBI’s Inspection Division,” the statement said. “As this is an ongoing matter, we have no further details to provide.”

Robertson, documents reveal, also threatened to kill New York County District Attorney Alvin Bragg in March 2023, who at the time was overseeing a criminal investigation into Trump regarding hush money payments provided to an adult film star. Trump has pleaded not guilty in this case.

“Heading to New York to fulfill my dream of iradicating (sic) another of George Soros two-bit political hach (sic) DAs,” Robertson wrote. “I’ll be waiting in the courthouse parking garage with my suppressed Smith & Wesson M&P 9mm to smoke a radical fool prosecutor that should never have been elected.”

This comment was posted under a Twitter account that has since been banned. In addition, officials said Robertson wrote on Facebook on Sept. 19, 2022, that the “time is right for a presidential assassination or two.”

“First Joe then Kamala,” Robertson said in a post referring to Biden and Vice President Kamala Harris. U.S. Attorney General Merrick Garland, California Gov. Gavin Newsom and New York’s Attorney General, Letitia James, were also targeted in social media posts.

Charles Marino, former Secret Service special agent and Homeland Security Department advisor, joined “The Hill on NewsNation” to provide expert analysis of the incident.

These “were direct threats,” he said. Not only against the president of the United States but also the vice president and other government officials involved with the cases against former President Donald Trump.

This story is developing. Refresh for updates.