No one kills nobody's mistress in this one, don't believe the synopsis and it's rather tedious and redundant, not the usual Fleischer's lot by far. Italian directors, Lenzi included, did similar revamping of Godfather much better. But Frederic Forrest is quite memorable here and watch for Victor Argo smashing a guy's head with a pipe.
A Godfather spin - off, and a very slow moving one. But what makes it a B - Gangster movie worth watching is the tautly managed action sequences, particularly the elaborate raid mounted by Forrest on Quinn`s headquarters and the climatic shooting.