Dramatic New Details from Natalie Wood Death Investigation

After 30 years, certain witnesses in the case of Natalie Wood's mysterious death are finally being interviewed by authorities. One witness says Wood and husband Robert Wagner were having such a heated argument the night she drowned, Wagner screamed

There are dramatic new details about the Natalie Wood death investigation, and what triggered the reopening of the case after 30 years.

The Los Angeles County Sheriff's Department now has sworn declarations from several witnesses who've come forward with explosive new claims about the night Natalie Wood drowned. One witness—who kept quiet until now—says she heard a woman in the water crying for help on that fateful night.

Marilyn Wayne told 48 Hours: Mystery, "I heard a woman calling for help: 'Help me somebody, please help me, I'm drowning!' "
Wayne said that her yacht was moored 50 yards from the Splendour, the boat where Wood was partying with husband Robert Wagner and actor Christopher Walken off Catalina Island over Thanksgiving weekend in 1981.

The new People magazine says that three days after Wood's death, Wayne says she found a hand-scribbled note in her mailbox that read, "If you value your life, keep quiet about what you know."

Another new development comes from the Splendour's captain, Dennis Davern. In his just-released sworn declaration to police, he describes an explosive fight on board, with a jealous Wagner, upset because he thought his wife was flirting with Walken, screaming at Wood, "Get off my […] boat!"

People's JoAnne Fowler told INSIDE EDITION, "In his new statement to police, the boat captain said that Robert Wagner came to him appearing disheveled, sweaty, and he said Natalie was missing. The boat captain went to Robert Wagner and he said, listen, should I turn on the search light? And [Wagner] said no, we're not going to do that right now."

And the Coast Guard captain who was first on the scene says in his new sworn statement to police that Wagner told him he hadn't called for help sooner because: "We thought she was off on another boat screwing around because that's the kind of woman she is."

Cops say Wagner is not considered a suspect in the new investigation. But the actor, now 81 and best known as the spokesman for Reverse Mortgages in TV ads, is reportedly extremely upset over the case being reopened.

His wife, actress Jill St. John, "is totally going crazy," according to the Chicago Sun-Times.

INSIDE EDITION found Christopher Walken in Los Angeles over the weekend, where he's filming a new movie.

Walken has hired a lawyer, a former federal prosecutor, in response to the reopening of the case.

And Wood's grave at Los Angeles's Westwood Village Cemetery has faded flowers on it, as the mystery surrounding her death 30 years ago fascinates a whole new generation.

According to a spokesman, Wagner has said the family trusts the Sheriff's Department to do a fair investigation.