Complex sentence: But Peters, a patriot, turned into an undercover for the FBI, he became close friends with Bill's father, Joe Bonanno Sr, even staying at Joe Bonanno's Tucson home.
Split into simpler sentences: But Peters, a patriot, turned into an undercover agent for the FBI. He became close friends with Bill's father, Joe Bonanno Sr, even staying at Joe Bonanno's Tucson home.