Continuity mistake: When Russ and Frank are in the hotel pool the woman in the left is holding a cigarette. In the close-up it swaps to a lemonade. Then in the wide angle it swaps back to a cigarette.
Continuity mistake: When Jimmy is sitting with Frank at the restaurant complaining about the fact that Tony Pro is late, we see Frank holding a Coca-Cola bottle with the right hand, but in the next shot the hand disappears from the table and stays down resting on the chair.
Continuity mistake: When Jimmy is in prison, eating a dish of ice cream while having a conversation with Tony Pro, the amount of ice cream in the dish keeps changing: there's more ice cream, there's less ice cream, there's more. Every shot the amount increases, then decreases next shot. Also, sometimes you can see a cherry stem in the dish and sometimes there's no cherry stem.
Chosen answer: First off his name was Chuckie O'Brian. Jimmy Hoffa wasn't his biological father, he was more in the nature of a foster father. Second, he probably knew what happened. What was Chuckie going to do? It was a sanctioned hit. And if he went to the police he would have ended up the same as Jimmy Hoffa. They put him in the middle of it to keep him quiet. If he goes after the people who did it, he's as good as dead. If he talks he could end up in jail with them, and the mafia will probably kill him anyway.