Vito made it very clear at the meeting where they made the peace that the deal was off if anything happened to Michael, "accidentally" or otherwise. It was only then they called off the dogs, but it was too late for Apollonia
"Io sono stanco, sono imbigliato, and I wan't everyone here to know, there ain't gonna be no trouble from me..Don Corleone..Cicc' a port!"
