(NewsNation) — An IRS agent claims that he and his entire team have been removed from an investigation regarding Hunter Biden, in what the agent’s lawyers say is a violation of whistleblower protection laws.

The criminal supervisory special agent was leading a team investigating the possibility that Hunter Biden, the son of President Joe Biden, was engaging in tax fraud. Lawyers for the agent sent the letter to the House Ways and Means Committee in Congress, asking for their attention to the matter.

Whistleblowers are protected under law, and the letter called attention to April testimony from IRS Commissioner Daniel Werfel, where he stated no employees would face retaliatory action for contacting a whistleblower hotline.

Previously, lawyers representing the agent had stated he wished to come forward to Congress with information about conflicts of interest in the investigation into Hunter Biden’s taxes. The federal investigation has been ongoing since 2018 and so far, no charges have been filed.

House Republicans have also been investigating Hunter Biden and other Biden family members for business dealings with foreign entities, including those based in Ukraine and China.

So far none of the investigations have provided any concrete evidence linking President Biden to his son’s business dealings and the president has said he did not discuss his son’s business endeavors with him.

The White House has said the president respects the independence of the Department of Justice and will not interfere with any investigations into his family.