washington u.s. president donald trump dismissal fbi director jam comey raise question future agency probe russian attempt sway 2016 presidential election possible collusion trump campaign justice department announce may 17 deputy attorney general rod rosenstein appoint former federal bureau investigation director robert mueller special counsel lead independent probe expect fbi investigation continue comey fire end fbi investigation moscow role 2016 election career fbi staffers comey put charge probe likely continue legal experts tell reuters even white house interview new directors probe underway u.s. congress also continue investigations already underway senate intelligence committee house intelligence committee panel progress congress could also create special commission appoint special master separate committee probe even mueller appointment experts say senate republicans include leadership previously argue appointment special counsel could imperil ongoing congressional probe mueller authority demand congress halt probe though criminal probe time complicate congressional matter legal experts say complications would indistinguishable create already ongoing fbi investigation mueller steer parallel probe justice department mueller interview relevant witness subpoena document evidence merit work fbi bring criminal charge relate probe mueller operate high degree independence trump administration rosenstein appoint mueller head department russia probe cite department regulations allow attorney general appoint special counsel outside federal government department regulations quite robust law relate appointment special prosecutor lapse 1990s accord justin levitt professor loyola law school los angeles regulations design give special counsel great degree independence decisions override make sure congress know levitt say rosenstein appoint mueller attorney general jeff sessions recuse involvement russia-related probe tell congress contact russian officials would difficult fire mueller job attorney general case rosenstein act attorney general matter relate russia authority fire special counsel justice department regulations state special counsel remove cause misconduct conflict interest dereliction duty levitt say though rosenstein like comey serve pleasure president could remove without cause time levitt caution order jeopardize mueller probe would come high political cost action come increase public congressional scrutiny levitt say factbox u.s. justice department 's special counsel probe russia