Hunter Biden has filed a lawsuit against the Internal Revenue Service, arguing that two agents violated his right to privacy when they publicly aired his tax information as they pressed claims that a federal investigation of him had been improperly handled.

The lawsuit filed Monday says that his personal tax details shared during congressional hearings and interviews was not allowed by federal whistleblower protections.

The suit escalates the legal fight as a long-running investigation continues to unfold against a sharply political backdrop, including an impeachment inquiry aimed at his father, President Joe Biden.

It comes days after Hunter Biden was indicted on federal firearms charges alleging that he lied about his drug use to buy and possess a gun in October 2018. The case could be on track toward a possible high-stakes trial as the 2024 election looms.

IRS supervisory special agent Greg Shapley, and a second agent, Joe Ziegler, have claimed there was pattern of “slow-walking investigative steps” into Hunter Biden in testimony before Congress. The Justice Department has denied any political interference in the case.

The IRS and lawyers for the two men did not immediately return messages seeking comment.