When he evaded conviction for several years, always going between the lines, and flamboyant dealings with suspicious people, however, when John F. Kennedy was elected president in 1960, he appointed his younger brother Robert F. Kennedy as attorney general.
Since he knew about that there were a lot of speculations, and about that, he could see these negotiations as to the secrets of various people around that, where the evidence was kept in places that would never be discovered.
There was a whole wave of negotiations, he would refer them to members who were secret representatives of his negotiations, and his dealers who were chosen in secret places, when Robert Kennedy had been thwarted.
During several previous attempts to convict Hoffa, even though some cases were never proven, the secrets and money of negotiations would never be discovered.