I have agreat idea of gf4, in the scene where fredo gets killed, the gun shot part isn't seen..

so think about it, the man that had to kill him couldnt do it, so he told fredo that michael send to kill him , and let him go. and shot to the air so michael will think he shot at him.

fredo escapes from the country, and comes back while vincent is the don, and michael is still alive, he kills both vincent and michael, and finaly findes the respect he looked for his whole life...