Robert Wagner FINALLY Answers Questions Over Natalie Wood Death In Dramatic Showdown

In an explosive public confrontation, actor Robert Wagner unwittingly revealed he murdered his movie-siren wife, Natalie Wood, 34 years ago, top experts who spoke to RadarOnline.com have sensationally claimed.

The shattering revelation came in a showdown between Wagner, 86, and Natalie's sister Lana, 69, at a Hyatt Regency hotel near Palm Springs, Calif., where he was attending a Feb. 12 awards ceremony for his actress-wife, Jill St. John.

The former star of the Hart to Hart didn't know he was being secretly videotaped when Lana hit him with the bombshell challenge: "Why won't you speak to the detectives?"

Barked Wagner, "Lana, why would you even bring up anything like that?"

Then, he furiously snapped: "I have talked to everybody. You have accused me! You have accused me of murdering her!"

As Lana stood with tears running down her cheeks, Wagner stalked off, saying: "I have stopped and said to you what happened."

As RadarOnline.com reported, Wagner was onboard the Splendour with Natalie, 43, and Christopher Walken, her leading man in Brainstorm, when she vanished from the boat the night of Nov. 29, 1981. She was later found drowned off California's Catalina Island.

Wagner has insisted he's innocent of harming her. But sources said he's stonewalled cops in their investigation by refusing to answer questions.

RadarOnline.com showed the video of the encounter to renowned voice stress analyst Michael Sylvestre.

Sylvestre insisted the aging Prince Valiant star was not telling the truth.

"When he happened to mention 'murder,' he was highly agitated — there was quite a bit of stress in his voice Sylvestre told RadarOnline.com.

"He knows why she is accusing him. She wants that answer and he is not giving it to her. He knows why he is being accused. It's a possibility that he is expressing some form of guilt."

Top body-language expert Susan Constantine also viewed the video and told RadarOnline.com that Wagner is "concealing information" by refusing to answer Lana's questions.

Constantine noted Wagner calling Natalie "her" — when he complained about being accused of "murdering her" — was a red flag.

"In all of my investigative training, what we have found is that when a person has murdered their spouse or child, they will call them 'her' or 'him,'" she explained. "They don't name them by their name as if to distance themselves from the person."

Wagner's lawyer, Blair Berk, has said the actor has "fully cooperated" with police and has vehemently denied any wrongdoing.

Woods' death was originally ruled an "accidental drowning." But in 2012, the cause-of-death ruling was changed to "drowning and other undetermined factors" citing strange bruises that were found on her body.

Splendour captain Dennis Davern has said a jealous Wagner had a violent fight with Natalie before she vanished from the boat. He also claimed Wagner delayed her search.

Lana told RadarOnline.com: "I want him Wagner to go to the police, cooperate with the detectives. I don't know why he won't do this!"