Michael Corleone's name was said so that the bartender or anyone else that may have been in the bar at the time, would hear what he said and eventually word would have goten around that Michael Corleone was the one who put the hit on Frank. That in itself would have caused much dissention amongst the families. It worked out even better, at first, because Frank did not die, so he sincerely believed that Michael was the one who tried to have him killed and therefore turned government witness. It almost worked out perfectly for Roth, but Michael was too swift once again!

Don Cardi