A part from GF2 that i never understood was when Pantangelli was "strangled" with the guy saying greetings from Michael Corleone.

I'm assuming Roth set this up in order for Frankie to feel betrayed by Michael.

Does Frankie ever realize this? - does seeing his brother with Michael at the trial make him realize this? - Even when Tom talks with him after the trial the subject isn't mentioned as far as i can tell

Thanks - one part that always confused me