A former prosecutor in the case of longtime Trump associate Roger Stone will testify that he and other career prosecutors were told to reduce their recommended sentence for Stone because the acting U.S. attorney at the time was "afraid of the president."

Aaron Zelinsky, who previously work on Special Counsel Robert Mueller III's investigation, will make the remarks at a House Judiciary Committee hearing Wednesday titled "Oversight of the Department of Justice: Political Interference and Threats to Prosecutorial Independence," according to a copy of his written opening statement released Tuesday.

Zelinsky was one of four career prosecutors who resigned from the criminal case against longtime Trump associate Roger Stone after Main Justice overrode the original trial team's sentencing recommendation for Stone.

Zelinsky wrote that prosecutors were asked to modify their calculation for Stone's sentence before the memorandum was filed with the court. "Ultimately, we refused to modify our memorandum to ask for a substantially lower sentence. Again, I was told that the U.S. attorney's instructions had nothing to do with Mr. Stone, the facts of the case, the law, or department policy. Instead, I was explicitly told that the motivation for changing the sentencing memo was political, and because the U.S. attorney was 'afraid of the president,'" the former Mueller prosecutor said in the statement.

Zelinsky wrote that he and the other three prosecutors learned of the new sentencing memo from media reports about a statement from an unidentified Justice Department official, and that other DOJ officials refused to share a copy of the revised memorandum before it was filed.

"Concerned over the political influence in the case—and the explicit statements that the reasons for these actions were political, and that the U.S. attorney was acting because he was 'afraid of the president'—I withdrew. My three colleagues did the same," Zelinsky wrote.

Another witness, John Elias of DOJ's antitrust division, will testify that he became "concerned enough to report certain antitrust investigations launched under Attorney General Barr to the Department of Justice Inspector General," asking the watchdog to "investigate whether these matters constituted an abuse of authority, a gross waste of funds, and gross mismanagement."

Among the antitrust investigations Elias flagged were those into mergers within the marijuana industry and "an investigation—initiated the day after tweets by President Trump—of an arrangement between the state of California and four automakers on fuel emissions."

"I have undertaken whistleblower activity, and am here today, because I recognize the imperative for law enforcers to operate even-handedly and in good faith," Elias' opening statement reads. "During my career at DOJ, I have been taught to do the right thing, for the right reasons, in the right way."

Also set to testify at Wednesday's hearing are former Deputy Attorney General Donald Ayer, who previously worked alongside Attorney General William Barr at the Justice Department, and former Attorney General Michael Mukasey.

Claims of political bias within the Justice Department have been amplified in recent months, over the Stone sentencing and more recently with the DOJ's request to dismiss the criminal case against onetime Trump national security adviser Michael Flynn. Such allegations were raised again over the Trump administration's firing June 19 of Geoffrey Berman, the U.S. attorney for the Southern District of New York, whose office housed other Trump-adjacent probes.

Read the prepared statements below:

Donald Ayer:

Aaron Zelinsky:

John Elias: