Did Cliff kill his wife?

Cliff seems like your friendly stunt-double friend. He has a dark cloud hanging over him. Many in the industry appear to believe that he killed his wife and got away with it. We are shown a flashback in which Cliff is on a boat with his wife who is continually insulting him. At one moment, Cliff has a harpoon pointed right at her, but then the scene cuts away and is never mentioned again. This scene also draws similarities to the mysterious death of actress Natalie Wood.