An Internal Revenue Service official has filed a whistleblower complaint alleging that at least one Treasury Department political appointee attempted to interfere with an audit of President Trump or Vice President Mike Pence's tax returns, The Washington Post reports. In an interview, the whistleblower told the Post he filed the complaint on July 29, and sent it to the tax committee chairs in Congress along with the Treasury Department Inspector General for Tax Administration. While the Trump administration reportedly dismissed the complaint as “flimsy” because it is based on second-hand evidence, the whistleblower said corroborating his claims are “what investigations are for.” He also denied being politically-motivated, and said he believed in “civil servants” acting with “integrity and perform our duties impartially, even at the risk that someone will make a charge of bias.”

Congressional Democrats were concerned enough by the complaint to flag it to a federal judge, and they are now reportedly considering making it public. A Treasury Department spokesman and the spokesman for the Treasury inspector general both declined to comment. Spokesmen for both Rep. Richard Neal (D-MA), chairman of the House Ways and Means Committee and Sen. Chuck Grassley (R-IA), Senate Finance Committee chair, both declined to talk about the complaint's details.