On Thanksgiving weekend 1981, Actress Natalie Wood drowned in the waters off Southern California’s Catalina Island while yachting with her husband, actor Robert Wagner, and her then co-star Christopher Walken. The star’s death was initially ruled an accident.

Watch: Natalie Wood Drowning: New Accounts Emerge Three Decades After Star’s Last Voyage

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Three decades later, Los Angeles County investigators reopened the case, changed the ruling from “accidental” to “undetermined” and named Wagner as a person of interest. Wagner denies any involvement in his late wife’s death. He has never been charged.

The actress’s sister, Lana Wood, says she believes the original investigation into Natalie’s drowning was “mishandled,” and that aspects of the investigation may have been covered up, or purposefully overlooked. Now that the investigation has been reopened, Lana claims Wagner isn’t talking to police about her sister’s death.

Watch: Why Natalie Wood’s Sister Claims Investigation Into Her Death Was ‘Mishandled From The Beginning’

“The only reason can be is that he has something to hide. Otherwise, why wouldn’t you talk to the police?” Wood asks in part one of a two-part Dr. Phil airing Thursday, adding, “Why wouldn’t you say ‘Ask me anything, of course.’?”

When Lana confronted her former brother-in-law in a hotel lobby, how did Wagner respond?

Watch the video above, then check here to find out where you can tune in to catch Thursday’s episode.

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Podcast Host Claims There’s Proof Natalie Wood’s Death Wasn’t An Accident