A repulsive murderer has himself been repulsively murdered

It's just crazy the cast on this one; Albert Finney, Lauren Bacall, Ingrid Bergman, Jacqueline Bisset, Sean Connery, Anthony Perkins, Vanessa Redgrave, Richard Widmark and so on. Wanted to see the movie because there's a remake (courtesy of Kenneth Branagh) on the way. Don't know if they're going to change the ending (disclosure of the murderer) with the remake - hopefully to do, not that there's nothing wrong with the ending, but there wouldn't be a point otherwise, would there?