The best link is the fact that Fredo's mistress runs out the house and says: " Two man.....before my window.....dead!!!!"
Gracias Diaz Paisans
Mighty expensive mistress, Deanna was Fredo's wife.[/b]
Whatever.
And Boss, your theory is not likely. When Corleone Button men kill them they would directly go to Michael and say it. And nobody did that. The found the persons dead and non of the button men had fired a single shot.
