As director of the FBI, Robert S. Mueller III transformed the agency into a terrorism-fighting force after the Sept. 11, 2001, attacks. But Mueller, who died in March, is perhaps best remembered as the special counsel in charge of investigating ties between Russia and Donald Trump's 2016 presidential campaign. March also saw the death of martial arts grandmaster and action star Chuck Norris. He appeared in a number of action movies over the years before his biggest role as the star of TV's "Walker, Texas Ranger." Other noteworthy people who died in March include former White House aide Alexander Butterfield, actor Mary Beth Hurt, Italian politician Umberto Bossi and musicians Darrell "Dash" Crofts and "Country" Joe McDonald.