William Barr, President Donald Trump’s choice to lead the Justice Department, has provided lawmakers a copy of his June memo to department officials, lambasting special counsel Robert Mueller III’s possible inquiry into whether Trump committed obstruction of justice.

The letter, which Barr wrote as a “former official,” is addressed to U.S. Deputy Attorney General Rod Rosenstein and Steven Engel, a former Dechert partner who now heads DOJ’s Office of Legal Counsel. The Kirkland & Ellis lawyer provided a copy of the memo to lawmakers on the Senate Judiciary Committee panel that will question him during his confirmation hearing.