American movie from late 60’s or very early 70’s

The only scene I remember, because it has haunted me, was from early in the movie.  A man, later to be revealed to be a married father, is being dragged by two men through the water, by a rope (tied to his legs?) in a motor boat until he dies.  I seem to remember he may have been a low level informant or a snitch and it was a mob rubout.  I remember the young wife being told her husband was dead.  I remember NOTHING else from the movie, but the murder was gruesome and terrifying.   Please help!

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