Special Counsel Robert Mueller has made his first public comments on his office’s investigation of Russian interference in the 2016 U.S. presidential election. The United States Department of Justice appointed Mueller to lead the investigation two years ago. The investigators uncovered numerous attempts to interfere with law enforcement, a crime known as obstruction of justice. On Wednesday, Mueller explained his decision not to propose legal action against U.S. President Donald Trump. He said that charging Trump with a crime was “not an option” that his team could consider. The special counsel added that if his office “had confidence that the president clearly did not commit a crime, we would have said so.” Mueller said his office was required to follow Justice Department policies. He noted a long-standing legal opinion that a president “cannot be charged with a federal crime while he is in office.” “That’s unconstitutional,” Mueller said.