I never understood Altobello or his motivations. Maybe he had something going with Zasa. But after Zasa's murder, what was in it for Altobello to hire the assassin? Seems as if Lucchese could have taken care of Michael by himself, given his power. [/quote]

The only thing I can think of is that Luchese promised Altobello money or power if he could get rid of Michael. If Luchese wanted Michael dead, then Altobello was his buffa.