The man who guided the FBI in the wake of the 9/11 terror attacks has been appointed as a special counsel to the investigation into the Trump campaign's links to Russia.
Robert Mueller - a trained lawyer with decorated military service in the Vietnam War - served as the director of the FBI from 2001 to 2013.
He took the post on September 4 2001 - one week before a string of terror attacks rocked America and the world.
His appointment by the Department of Justice comes one week after his predecessor within the FBI, James Comey, was fired by Donald Trump.
The US President is said to have reacted to the news quietly, but also defiantly.
See his life story below: