reporter: none of the preefs directors had finished their ten year terms let alone exceed them. extending mueller requires congress to pass a new law which clears the senate unanimously. the decision to extend bob mueller term is the only time it happened. it was remarkable testament to him that congress approved this. reporter: muellers two year extension ends in 2013. he hands a completely over hailed fbi to a new director james comey. a man who four years later play a major role in the initial faze of the russia investigation. a full fledge member of the u.s. intelligence community and not just premier law enforcement agency in the united states. he earned the respect of the american people. with the concept that america is at peace because the fbi is at war. reporter: after leaving the fbi. mueller hired as a partner at the law mirm will hail.