It's somewhat surprising John DiFronzio didn't get indicted the first time. Nick Calabrese testified that he participated in the Spilotro murders, which is what Marcello was ultimately convicted of, but they apparently didn't have any other evidence besides Nick's testimony.

For Marcello Michael Spilotro's daughter made a "voice ID" over the phone... I think that was it.

Hard to believe that a 40-year-old voice ID was the only thing that separated Marcello from being indicted (at least on that charge) and letting DiFronzio go. However, I think Marcello was also convicted of other stuff.

Forgive me if I got anything wrong in the above, it's been a while since I revisited that trial.