AP

Natalie Wood and Robert Wagner in 1980.

Robert Wagner has been fielding questions about Natalie Wood's death for more than 31 years -- and, at this point, he has nothing left to add to the discussion.

So says the actor's attorney, Blair Berk, who said Thursday that Wagner won't be interviewed yet again by authorities as they continue to investigate Wood's death on Nov. 28, 1981, off the coast of Catalina Island. A newly released coroner's report that expanded on the original medical examiner's findings has attributed her death to "drowning and other undetermined factors."

"Mr. Wagner has fully cooperated over the last 30 years in the investigation of the accidental drowning of his wife in 1981. Mr. Wagner has been interviewed on multiple occasions by the Los Angeles Sheriff's Department and answered every single question asked of him by detectives during those interviews," Berk said in a statement to E! News.

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"After 30 years, neither Mr. Wagner nor his daughters have any new information to add to this latest investigation, which was unfortunately prompted by those seeking to exploit and sensationalize the 30th anniversary of the death of his wife and their mother."

The investigation -- which originally concluded that Wood died in an accidental drowning, period -- was reopened in 2011 after the Los Angeles County Sheriff's Department was contacted by "persons who stated they had additional information." Sheriff Lee Baca said at the time that Dennis Davern, the captain of Wagner's boat, the Splendour, had made comments "worthy of exploring."

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According to the Los Angeles Times, authorities are currently pursuing new leads based on witnesses and evidence that detectives did not take into consideration the first time around. The new coroner report, in addition to amending the cause of death, also cited "conflicting statements" as to when Wood was last seen on the boat by her husband and their guest, Christopher Walken.

-- additional reporting by Claudia Rosenbaum

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Natalie Wood's death certificate has been changed to reflect some of the uncertainties and lingering questions surrounding the actress' drowning more than 30 years ago in the Pacific Ocean off Southern California.

The document was amended earlier this month and shifts Wood's death from an accidental drowning to "drowning and other undetermined factors," according to a copy of the certificate obtained Tuesday by The Associated Press.

The amended document also now states that the circumstances of how Wood ended up in the waters off Catalina Island in November 1981 are "not clearly established."

The changes occurred nine months after sheriff's homicide investigators renewed their inquiry into Wood's death shortly before its 30th anniversary.

Chief of Detectives William McSweeney said the decision to amend the death certificate was ultimately made by the coroner's office, which has been instructed by detectives not to discuss the case. "I would just say undetermined is descriptive," he said.

AP

Natalie Wood's death certificate, which was amended on Aug. 1, 2012.

McSweeney said detectives still have work to do on the case, but that doesn't necessarily mean that a major shift is coming.

"We don't close these cases," he said. "These cases have active periods and more passive periods. We're moving toward the end of an active period."

The changes to the death certificate were approved by Los Angeles County Chief Medical Examiner Dr. Lakshmanan Sathyavagiswaran in late June, but they were not formally recorded until Aug. 1. The certificate wasn't made public until just recently.

Conflicting versions of what happened on the yacht shared by Wood, her actor-husband Robert Wagner and their friend, actor Christopher Walken, have contributed to the mystery of how the actress died on Thanksgiving weekend in 1981. Authorities have said Wagner is not a suspect in his wife's death.

Investigators re-opened the case last November but have released few details about its progress. They traveled to Hawaii to inspect the Splendour, the yacht the trio was aboard on the night of Wood's disappearance.

The renewed inquiry came after the boat's captain, Dennis Davern, told "48 Hours Mystery" and the TODAY show that he heard Wagner and Wood arguing the night of her disappearance and believed Wagner was to blame for her death.

Wagner wrote in a 2008 memoir that he and Walken argued that night. He wrote that Walken went to bed and he stayed up for a while, but when he went to bed, he noticed that his wife and a dinghy attached to the yacht were missing. 

Wagner has said through a spokesman that he expects the sheriff's department to conduct a fair investigation. An email seeking comment Tuesday was not returned. 

Wood was nominated for three Academy Awards during her lifetime. Her death stunned the world and has remained one of Hollywood's most enduring mysteries. The original detective on the case, Wagner, Walken and until recently, the coroner's office, have all said they considered her death an accident. 

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The family of Robert Wagner "fully supports" the investigation into Natalie Wood's accidental drowning, 30 years later. As for the family of Natalie Wood -- specifically her sister Lana -- she told TODAY's Matt Lauer Monday that she has mixed feelings about the investigation into Natalie's death being reopened. "I'm scared, I'm nervous, I'm happy, I think. I'm so ambivalent. It's almost like having to relive her death again," Lana said.

Lana told Lauer that she spent the last 30 years since Natalie's death preferring to believe that her death aboard the boat the Splendour with Wagner was really just an accident, as it was ruled shortly after it happened. "It's been easier that way," Lana said, despite things not adding up. "You want to think the best."

The Splendour's captain Dennis Davern told David Gregory during a Nov. 18 interview on TODAY that the fight between Natalie and Wagner is what led to Natalie's drowning. To that assertion, Lana told Lauer that the captain had called her "many many years ago," suggesting there was more to the story, and that he was very upset "and trying to unburden himself."

Davern went on to assert during that Nov. 18 interview that no effort was made to search for Natalie after she was lost overboard. "Unfortunately, I do believe him," Lana told Lauer.

You can watch the entire interview above.

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TODAY

Natalie Wood and Robert Wagner in an undated photo.

In an uncomfortable interview on NBC's TODAY, the former captain of the boat off which actress Natalie Wood drowned in 1981 alleged that her husband, actor Robert Wagner, was responsible for her death.

(Msnbc.com is a joint venture of Microsoft and NBC.)

Dennis Davern, once captain of the couple's boat, The Splendour, is now urging homicide investigators to take another look at the 30-year-old case. Wagner, a Hollywood beauty known for roles in films like "Rebel Without a Cause" and "West Side Story," was working on the 1983 film "Brainstorm" with actor Christopher Walken at the time. Walken was on the boat with the couple when Wood died.

During the TODAY interview, Davern appeared reticent and unwilling to tell interviewer David Gregory what happened or what he was alleging. When pressed, he did say "I made some terrible decisions and mistakes. ... I made mistakes by not telling the honest truth in a police report."

When further pressed by Gregory, Davern said he believed Wagner had intentionally kept the investigation into her death low-profile. And when asked if he thought Wagner was "responsible" for Wood's death, Davern said, "yes, I would say so. Yes."

Davern is co-author, with Marti Rulli, of the 2009 book "Goodbye, Natalie, Goodbye, Splendour." Rulli also appeared on TODAY. She told Gregory that when Wood disappeared after a reported fight with Wagner, Davern wanted to help in the search but was dissauded by the actress' husband.

"Dennis wanted to do everything. Make a phone call , turn on the searchlight," Rulli said. "His instincts told him something was terribly wrong, and Robert Wagner asked him not to."

KTLA reports that according to Wagner's account of the night, the argument concerned Wood's balance of personal life vs. career, and he we was upset that Walken was advocating that Wood focus on acting even at the expense of her husband and children.

Reports in the past have said that Wood may have been trying to board or secure a dinghy attached to the boat and instead slipped and fell into the water. She was wearing a down jacket over a nightgown when her body was found. The case has never completely been settled in the minds of many fans, particularly because Wood once said in an interview that dark seawater was her greatest fear.

The L.A. County Sheriff's Department announced Thursday that it had reopened the investigation into Wood's death.  A news conference has been scheduled for 11 a.m. PT Friday with the detective leading the investigation.

In a statement, Wagner said Thursday that he supports the new investigation, but with the caveat that he trusts any new information used in the investigation will come "from a credible source or sources other than those simply trying to profit from the 30 year anniversary of her tragic death."

Davern told Gregory, "I'm far away from even thinking about profiting over a 30-year anniversary. I have known this information for many, many years. And my book has been out for two years. I'm not in it for any kind of profit. I'm in it for the justice of the whole situation."

We will continue to update this story. Watch the video below to see Davern and Rulli's interview with David Gregory.

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