id have to watch part 2 again to maybe pick up on something but what i notice is people doubting fredo did it because of the fact he was "innocent and sweet"...just because you SEE him that way doesnt always mean hes that way and as for saying he didnt know it was gonna be a hit...IMO thats just his way of coverin his ass so he wouldnt get whacked but as michael saidi n the first film "you think that would fool a corleone" and remember that fredo did get pissed at michael in the first one for the casino deal and michael told him not to take sides against the family again so if you use that and follow chronologically then i say fredo knew what he was doing it was his way of getting back at michael but a failed hit and the obvious person will always try to cover their ass