By FARNOUSH AMIRI (Associated Press)

WASHINGTON (AP) — House Republicans on Thursday requested voluntary testimony from nearly a dozen Justice Department officials involved in the investigation of President Joe Biden’s son Hunter as GOP lawmakers widen their scrutiny into what they claim is improper interference by the agency.

Leaders of the Republican-controlled House Judiciary, Oversight and Accountability, and Ways and Means committees asked in a letter to Attorney General Merrick Garland for nine officials from the Justice Department and two from the FBI to appear for the interviews to address recent allegations made by two IRS employees who worked on the federal investigation into Hunter Biden’s taxes and foreign business dealings.

“Recent startling testimony from Internal Revenue Services whistleblowers raises serious questions about the Department’s commitment to evenhanded justice and the veracity of assertions made to the Committee on the Judiciary,” Reps. Jim Jordan of Ohio, James Comer of Kentucky and Jason Smith of Missouri wrote in the letter obtained by The Associated Press.

The individuals named in the letter include David Weiss, the U.S. attorney in Delaware in charge of the investigation, as well Assistant U.S. Attorney Lesley Wolf of Delaware and the top federal prosecutor for the District of Columbia Matthew Graves. Garland said last week that the Justice Department will not object to Weiss testifying to Congress.

A department spokesperson confirmed receipt of the letter but declined further comment.

The request comes about a week after Biden, 53, reached an agreement with the government to plead guilty to misdemeanor tax offenses. The plea deal would also avert prosecution on a felony charge of illegally possessing a firearm as a drug user, as long as Biden adheres to conditions agreed to in court.

Days later, the House Ways and Means Committee, led by Smith, voted to publicly disclose congressional testimony from the IRS employees.

The testimony from Greg Shapley and an unidentified agent detailed what they called a pattern of “slow-walking investigative steps” and delaying enforcement actions in the months before the 2020 election won by Joe Biden.

It is unclear whether the conflict they describe amounts to internal disagreement about how to pursue the investigation or a pattern of interference and preferential treatment. Department policy has long warned prosecutors to take care in charging cases with potential political overtones around the time of an election, to avoid influencing the outcome.

The Justice Department has denied the claims and said Weiss, appointed to his job when Donald Trump was president, had full authority over the case.

The letter provided a deadline of July 13 for the department to begin scheduling the individuals for transcribed interviews. It said that if the deadline is not met, the committee chairmen will resort to using a congressional subpoena to force cooperation.

Beyond Hunter Biden, the House Oversight and Accountability Committee led by Comer has undertaken a broader review of the Biden family’s finances and foreign dealings, issuing dozens of subpoenas to business associates and financial institutions.

Republicans have focused much attention on an unverified tip to the FBI that alleged a bribery scheme involving Joe Biden when he was vice president. The unsubstantiated claim, which first emerged in 2019, was that Biden pressured Ukraine to fire its top prosecutor in order to stop an investigation into Burisma, an oil-and-gas company where Hunter Biden was on the board.

Democrats said in a letter Thursday to Comer that the Justice Department investigated the claim when Trump was president and closed the matter after eight months, finding “insufficient evidence” that it was true. Democrats highlighted the transcript of an interview with Mykola Zlochevsky, Burisma’s co-founder, in which he denied having any contact with Joe Biden while Hunter Biden worked for the company.

“Mr. Zlochevsky’s statements are just one of the many that have debunked the corruption allegations,” said the committee’s top Democrat, Maryland Rep. Jamie Raskin.