The drowning of 43-year-old actress Natalie Wood in the waters off Southern California’s Catalina Island in November 1981 was initially reported as “accidental.” Then in 2011, investigators reopened the case and changed the ruling on Wood’s death to “undetermined.”

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Natalie and her husband, actor Robert Wagner, had been spending Thanksgiving weekend onboard their 55-foot yacht, “Splendour,” along with friend Christopher Walken. Walken was then co-starring with Natalie in what turned out to be her final film, 1983's “Brainstorm.”

“There were only four people on board, and three of those remain alive,” says Dylan Howard, investigative journalist and host of the podcast Fatal Voyage: The Mysterious Death of Natalie Wood. He claims two of those witnesses are talking to police, but “One is refusing to answer questions. And that is Robert Wagner.”

Watch: Former Yacht Captain Claims To Recall New Details From The Night Actress Natalie Wood Drowned

Robert Wagner adamantly denies any involvement with Natalie’s drowning and has never been charged in connection with his late wife’s death.

What did witnesses initially say happened aboard the “Splendour” the night Natalie Wood drowned? Have their accounts changed in the 37 years since the film star’s death? Watch the video above to find out why the investigation has been re-opened. Then, tune in to part one of this two-part episode Thursday to hear Natalie’s sister, Lana Wood, explains why she believes her sister may have been murdered.

Watch: Actress Natalie Wood’s Sister Claims Former Brother-In-Law, Robert Wagner, Has ‘Something To Hide’ In Drowning Investigation

Check here to find out where you can watch.

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