WASHINGTON (AP) — Treasury Secretary Steven Mnuchin said Wednesday he has no idea who wrote a confidential Internal Revenue Service legal memo that says that tax returns must be given to Congress unless the president asserts executive privilege.

Appearing before the House Financial Services Committee, Mnuchin said he was not aware of the existence of the memo until reporters from The Washington Post made inquiries about it.

Mnuchin noted that it was a draft document. He told the committee he believed he was following the law by refusing to turn over six years of President Donald Trump’s tax returns, which have been requested by Ways and Means Committee Chairman Richard Neal, D-Mass.

Mnuchin said he expected the dispute to ultimately be decided by the courts.

Mnuchin has refused to turn over the tax returns despite a 1924 law that gives the chairs of the tax-writing committees in Congress the power to request the returns of any taxpayer.

Mnuchin last Friday refused to obey a congressional subpoena to turn over the returns, saying he request “lacks a legitimate legislative purpose.”

Mnuchin told lawmakers that he had not had any discussions on the issue with Trump, who has said repeatedly that he can’t turn over his taxes because he is under IRS audit. Trump has not asserted executive privilege to protect the returns.

Neal has said he expects to bring a lawsuit to force the administration to comply with his subpoena.