U.S. Attorney for the Central District of California E. Martin Estrada, a Biden appointee, is set to testify behind closed doors on Tuesday before the House Judiciary Committee about Special Counsel David Weiss’s probe into Hunter Biden, a source familiar confirmed to Breitbart News.

IRS whistleblowers contend Estrada refused to cooperate with Weiss on potentially charging the president’s son in his district for tax violations. The New York Times confirmed the allegation in June, along with Biden-appointed U.S. Attorney for D.C. Matthew Graves — who also balked at partnering with Weiss — and IRS agent Darrell Waldon.

U.S. Federal Prosecutor E. Martin Estrada talks with reporters on March 30, 2023, in Los Angeles, California. (Luis Sinco / Los Angeles Times via Getty Images)

Waldon, IRS whistleblower Gary Shapley’s boss, was the fourth individual involved in the Hunter Biden case to voice concerns about President Joe Biden’s Justice Department (DOJ) blocking charges against Hunter Biden.

Shapley contends the DOJ twice prevented Weiss from bringing stronger charges against Hunter Biden, including in separate jurisdictions of Washington, DC, and California, and that Weiss said in an October 7, 2022, meeting he was “not the deciding person” in the probe.

RELATED: IRS Whistleblower Speaks Publicly for First Time, Says DOJ Intervened to Slow-Walk Hunter Probe to “Benefit” Him

Attorney General Merrick Garland disputes the whistleblower claims. Garland testified in September that nobody had the authority to block Weiss from charging Hunter Biden, though “they could refuse to partner with him.”

“No one had the authority to turn him down; they could refuse to partner with him,” Garland told House Judiciary Committee Chair Jim Jordan (R-OH).

“You can use whatever language — ‘refuse to partner’ is turning down,” Jordan replied.

“It is not the same under a well-known Justice Department practice,” Garland claimed.

However, a current FBI agent corroborated in September that “other processes” undercut Weiss’s authority to potentially charge the president’s son.

As Estrada is expected to testify behind closed doors, Weiss will also reportedly testify behind closed doors on November 7 about the probe. House Republicans want Weiss to clear up the contradictions between the whistleblower testimonies and DOJ claims.

Follow Wendell Husebø on Twitter @WendellHusebø. He is the author of Politics of Slave Morality.