Hunter Biden sued the Internal Revenue Service on Monday, saying that investigators for the agency violated his privacy rights by disclosing details to Congress and the public about his taxes and the investigation into his conduct.
Mr. Biden, the president’s son, filed the suit days after the Justice Department indicted him on separate charges relating to his purchase of a handgun in 2018. The decision to go ahead with the suit shows that he and his legal team are continuing to take an aggressive stance in fending off inquiries from congressional Republicans even as he faces the possibility of further prosecution on tax charges by the Justice Department amid his father’s re-election campaign.
The suit, filed in Federal District Court in Washington, asserts that I.R.S. investigators violated the agency’s rules on taxpayer privacy and “targeted and sought to embarrass Mr. Biden via public statements to the media in which they and their representatives disclosed confidential information about a private citizen’s tax matters.”
It points to the public testimony and statements by two I.R.S. investigators, Gary Shapley and Joseph Ziegler, who have been providing information to House committees seeking evidence of wrongdoing by President Biden and his family. Mr. Shapley and Mr. Ziegler have told House Republicans that they believe the Justice Department inquiry into Hunter Biden’s taxes was influenced by politics.
That claim has been disputed by Attorney General Merrick B. Garland and David C. Weiss, the U.S. attorney for Delaware who has overseen the case and was recently given special counsel status by Mr. Garland.
Hunter Biden “has all the same responsibilities as any other American citizen, and the I.R.S. can and should make certain that he abides by those responsibilities,” the suit says.
“Similarly, Mr. Biden has no fewer or lesser rights than any other American citizen, and no government agency or government agent has free reign to violate his rights simply because of who he is,” it says. “Yet the I.R.S. and its agents have conducted themselves under a presumption that the rights that apply to every other American citizen do not apply to Mr. Biden.”
The I.R.S. agents, their lawyers and House Republicans have said they followed the law in how the information about Mr. Biden was disclosed to Congress. They have said the disclosures were legally protected because they were covered by whistle-blower protections and were ultimately made public by the House Ways and Means Committee, which has jurisdiction over tax issues.
The suit, filed by Mr. Biden’s lawyer, Abbe Lowell, disputes that argument. Aside from the disclosures to Congress, the suit says, the agents and their lawyers made public other details about the investigation to the news media in more than 20 interviews and public statements.
“These agents’ putative ‘whistle-blower’ status cannot and does not shield them from their wrongful conduct in making unauthorized public disclosures that are not permitted by the whistle-blower process,” the suit says.
Along with making claims that Mr. Biden received preferential treatment from the Justice Department, the I.R.S. agents have disclosed details from the investigation that were potentially damaging to Mr. Biden and his father. A search warrant uncovered evidence that Hunter Biden had invoked his father — who was out of office at the time — while pressing a Chinese businessman to move ahead with a proposed energy deal.
“Tell the director that I would like to resolve this now before it gets out of hand, and now means tonight,” Mr. Biden wrote, referring to other participants in the proposed deal. “And, Z, if I get a call or text from anyone involved in this other than you, Zhang, or the chairman, I will make certain that between the man sitting next to me and every person he knows and my ability to forever hold a grudge that you will regret not following my direction.”
House Republicans have maintained that the investigators’ disclosures to Congress were legal because they were revealing government corruption.
While the suit involves the I.R.S., it is not directly related to the Justice Department’s investigation into Mr. Biden’s conduct.
In June, Mr. Biden and Mr. Weiss’s office announced they had reached a deal in which Mr. Biden would plead guilty to misdemeanor tax charges and a separate agreement to head off a gun charge.
Mr. Biden’s side believed the deal marked the end of the long-running investigation, which Republicans and former President Donald J. Trump hoped would inflict political damage on the president.
But the plea deal came apart at the last minute, during a court hearing in July. Mr. Weiss’s office indicted Mr. Biden last week on three counts of violating gun laws, alleging that he had lied about his drug use on a federal form when he purchased a handgun in Delaware five years ago.
Mr. Biden could also still be indicted on tax charges related to the late filing of his returns for a number of years and disputes over deductions he took.
Seamus Hughes contributed reporting.
