A group of senior Congressional Republicans are demanding an investigation into what they call "unlawful whistleblower retaliation against veteran IRS employees" involved in an investigation into the president's son, Hunter Biden.

In a letter sent Wednesday to special counsel Henry Kerner, whose office is responsible for investigating claims of retaliation against federal whistleblowers, Senators Chuck Grassley and Ron Johnson and Reps. Jason Smith, James Comer and Jim Jordan said IRS officials violated "anti-gag" rules that protect federal employees. The letter is the latest effort by Republicans to seize on whistleblowers' allegations that investigators were impeded by supervisors during their yearslong probe. They are also requesting a briefing on steps taken by Kerner's office by July 19.

In the letter they cited two internal emails by IRS administrators. In one, GOP lawmakers allege a special agent in charge reminded personnel on May 19 that case information could not be shared without "seeking approval" from a supervisor. In another, sent on May 25, GOP lawmakers allege an IRS deputy commissioner wrote in an email that the agency is "deeply committed" to whistleblower protections, but the Republicans said the email "fails to inform IRS employees of their Constitutional and statutory right to make protected disclosures to Congress."

"The Deputy Commissioner's email states IRS employees may make (disclosures) to a supervisor, management, the DOJ Office of the Inspector General, or the Treasury Inspector General for Tax Administration but blatantly fails to provide that IRS employees have the right to make lawful disclosures to Congress," the Congressmen wrote.

In Wednesday's letter, the Congressional Republicans wrote that "IRS employees have the right to make lawful disclosures to Congress if they believe a tax return or return information 'may relate to possible misconduct, maladministration, or taxpayer abuse.'"

"The importance of protecting whistleblowers from unlawful retaliation and informing whistleblowers about their rights under the law cannot be understated," they wrote.

A spokesperson for Kerner's office confirmed the letter was received Wednesday.

"We are in the process of reviewing it," said the spokesperson, Zachary Kurz.

Delaware U.S. Attorney David Weiss, a Trump appointee who has overseen the five-year-long investigation, said in a court filing on June 20 that Hunter Biden agreed to enter a guilty plea to two misdemeanor tax counts and judicial diversion related to a felony gun charge. The deal with prosecutors will have to be approved by a judge at a hearing which is currently set for July 26. 

The allegations of retaliation were first aired by IRS supervisory agent Gary Shapley, whose attorneys wrote in a May letter to members of Congress that he and his team had been removed from the investigation "at the request of the Department of Justice." He was one of two IRS investigators to testify behind closed doors to members of Congress on May 26 and June 1.

"I documented what I saw, and ultimately that's the evidence. If they want to explain how that's wrong, they can," Shapley told CBS News last week. "All of the things that I've testified in front of the House Ways and Means Committee is from my perspective, but it's based on the experience I've gained over 14 years."

Weiss pushed back against allegations of retaliation in a June 30 letter to Jordan, the House Judiciary Committee Chair. 

"The Department of Justice did not retaliate against 'an Internal Revenue Service ("IRS") Criminal Supervisory Special Agent and whistleblower, as well as his entire investigative team,'" Weiss wrote, quoting a June 22 letter from Jordan. 

Jordan and other House Republicans have asked the Justice Department to make Weiss available for closed-door interviews with Congress. Weiss said in his letter he would meet with Congress "at the appropriate time," but said he could not while the Hunter Biden investigation is ongoing.

"I welcome the opportunity to discuss these topics with the Committee in more detail, and answer questions related to the whistleblowers' allegations consistent with the law and Department policy," Weiss said.

Also on June 30, an attorney for Hunter Biden accused House Republicans of using the whistleblower claims in an attempt to derail the plea deal.

"To any objective eye your actions were intended to improperly undermine the judicial proceedings that have been scheduled in the case," attorney Abbe Lowell wrote to Smith, the House Ways and Means Chair. 

The two IRS whistleblowers began the process of coming forward months before their closed-door testimony to the GOP-controlled House Ways and Means Committee. 

Asked on June 23 about Shapley's testimony, the White House referred to a previously released statement. 

"President Biden has made clear that this matter would be handled independently by the Justice Department, under the leadership of a U.S. attorney appointed by former President Trump, free from any political interference by the White House," the statement said. "He has upheld that commitment."

In:
• Internal Revenue Service
• Hunter Biden

Catherine Herridge

Catherine Herridge is a senior investigative correspondent for CBS News covering national security and intelligence based in Washington, D.C.

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