(FILES) US President Barack Obama applauds outgoing Federal Bureau of Investigations (FBI) director Robert Mueller (L) in the Rose Garden at the White House in Washington, DC on June 21, 2013 as he nominates Jim Comey to be the next FBI director. Mueller, the former FBI director who led a politically explosive investigation into President Donald Trump, has died aged 81, US media reported Saturday. (Photo by Nicholas KAMM / AFP via Getty Images)