Who took over from Frankie? I really cannot guess other than Cicci. As I posted above, we are not apprised of any other characters who could do so except Neri and Lampone who were cemented into their roles in Nevada.
Oli, I don't understand: Are you saying that, after Cicci testified at the Senate hearing that Michael Corleone was the head of the Corleone crime family that he served, and that, as a button man, he killed people "at the behest" of his superiors, the Feds let him walk away, and then Michael rewarded Cicci by putting him in charge of the Olive Oil Business?
