In an Aug. 21, 2013 file photo, outgoing FBI director Robert Mueller speaks during an interview at FBI headquarters, in Washington. Muller, the special counsel investigating possible ties between President Donald Trump's campaign and Russia's government has taken over a separate criminal probe involving former Trump campaign chairman Paul Manafort, and may expand his inquiry to investigate the roles of the attorney general and deputy attorney general in the firing of FBI Director James Comey, The Associated Press has learned.

(Evan Vucci / AP)