Attorneys for an Internal Revenue Service whistleblower said their client, who has claimed the ongoing investigation into Hunter Biden’s taxes was mishandled, has been removed from the probe.

“Today the Internal Revenue Service (IRS) Criminal Supervisory Special Agent we represent was informed that he and his entire investigative team are being removed from the ongoing and sensitive investigation of the high-profile, controversial subject about which our client sought to make whistleblower disclosures to Congress,” the attorneys wrote in a letter to Congress obtained by The Hill.

The attorneys said the whistleblower was notified he was being removed from the probe at the Justice Department’s request. The agent alleged earlier this year that the IRS investigation into Biden’s taxes was being mishandled and asked for whistleblower protection in exchange for his information into the investigation.

The attorneys said the move to remove the whistleblower is “clearly retaliatory and may also constitute obstruction of a congressional inquiry.” The attorneys also pointed to IRS Commissioner Daniel Werfel’s testimony last month, in which he said those making a whistleblower claim will face “no retaliation.”

“We respectfully request that you give this matter your prompt attention,” the attorneys wrote in their letter to the chairs and ranking members of relevant House and Senate committees.

“Removing the experienced investigators who have worked this case for years and are now the subject-matter experts is exactly the sort of issue our client intended to blow the whistle on to begin with.”

The Hill has reached out to the IRS and Justice Department for comment on the letter.

It comes as House Republicans have launched multiple investigations into Biden, including his ties with foreign entities, his taxes and other financial records. President Biden has denied he has any knowledge of his family’s financial dealings amid the ongoing probes.