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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Some of the bruises on Natalie Wood's body may have occurred before the actress wound up in the water off California's Catalina Island in 1981, leading the Los Angeles Coroner's Office to change her cause of death to "drowning and other undetermined factors."

The actress' death certificate was amended back in August 2012, with the cause of death being changed from an accidental drowning to "drowning and other undetermined factors." But information as to why the change was made was not released until Monday, when the corner's office put out a 10-page supplement to the actress' autopsy report.

The supplement notes that "bruises especially in the upper extremities appeared fresh and could have occurred before (Wood) entered the water." It also says that "the location of the bruises, the multiplicity of the bruises, lack of head trauma, or facial bruising support bruising having occurred prior to the entry into the water."

Wood died after spending an evening on the 60-foot yacht Splendour with husband Robert Wagner and actor Christopher Walken in November 1981.

How exactly Wood, 43 at the time, ended up in the water is also unclear. In part because Wood was found wearing a flannel nightgown and down jacket, and because she is believed to have gone into the water around midnight, the supplement states that "this medical examiner is unable to exclude non-volitional, unplanned entry into the water."

Wood's bruises are described as "superficial skin bruises on the extremities and abrasions on the left side of the face."

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"There will be no further statement by the coroner regarding the Natalie Wood death injury," Chief Coroner Investigator & Chief of Operations Craig Harvey told NBC News.

Wood's body was found near a 13-foot dinghy, the Valiant, that had been attached to the boat but was located near the island's shore. The dinghy could not be located for the 2012 investigation.

In 2011, Dennis Davern, captain of the Splendour, publicly urged homicide investigators to look further into Wood's death. He co-authored a 2009 book about the case, "Goodbye Natalie, Goodbye Splendour."

Also in 2011, Davern told NBC's David Gregory on TODAY that he had "made some terrible decisions and mistakes" relating to his own reporting of the events, admitting that he had lied on a police report.

Davern also said he thought Wood's husband, Wagner, had intentionally kept the investigation into his wife's death low-profile and was "responsible" for her death. Police in 2011 said Wagner was not a suspect in his wife's death.

Wood starred in films including "Rebel Without a Cause," "West Side Story" and "Splendor in the Grass."

Related content:

• August 2012: Wood's death certificate amended by coroner
• November 2011: Captain says Wagner responsible for Wood's death
• November 2011: Police say Robert Wagner not a suspect

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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Getty Images file

Updated at 9:14 p.m. PT

Homicide investigators are reopening an investigation into the death of actress Natalie Wood, who drowned in 1981 while boating off the California coast, the Los Angeles County Sheriff's Department said on Thursday.

"Recently sheriff's homicide investigators were contacted by persons who stated they had additional information about the Natalie Wood Wagner drowning," the sheriff's department said in a written statement.

"Due to the additional information, Sheriff's Homicide Bureau has decided to take another look at the case," the statement said.

Sheriff's spokesman Steve Whitmore declined to release details about what information investigators received.

A news conference has been scheduled for 11 a.m. PT Friday with the detective leading the investigation.

The actress drowned after a night of partying with husband Robert Wagner and "Brainstorm" co-star Christopher Walken on the couple's yacht anchored off Santa Catalina Island. Her death at age 43 was ruled an accident and it was determined that she had been drinking before her death.

The sheriff's office wrote that Wood was "possibly attempting to board the dinghy and had fallen into the water, striking her face."

A dinghy that had been attached to the couple's yacht, "Splendor," was found in a Catalina cove.

The case has become one of Hollywood's most alluring mysteries. Wood's drowning sparked tabloid speculation that foul play was involved, but Wagner and Wood's sister have dismissed any suggestion there was foul play.

Harrington / AP, file

The 55-foot yacht "Splendour" sits in the waters off Catalina Island in Santa Catalina, Calif., near the site where Harbor Patrol personnel and lifeguards discovered the body of Natalie Wood.

Lana Wood wrote in a biography on her sister, "What happened is that Natalie drank too much that night."

The Los Angeles Times reported that detectives were prompted to look at the case again after comments by the ship's captain, Dennis Davern. He was recently interviewed for a collaboration between the magazine Vanity Fair and the television series "48 Hours Mystery" that focuses on Wood's death.

The Times, citing anonymous sources, reported that the sheriff's department had also received an anonymous letter saying that the captain had new recollections about the case.

"Although no one in the Wagner family has heard from the LA County Sheriff's department about this matter, they fully support the efforts of the LA County Sheriff's Dept. and trust they will evaluate whether any new information relating to the death of Natalie Wood Wagner is valid, and that it comes from a credible source or sources other than those simply trying to profit from the 30 year anniversary of her tragic death," Wagner spokesman Alan Nierob wrote in a statement.

Wagner wrote in a 2009 autobiography that he blamed himself for his wife's death.

He recounted the night of Wood's disappearance, during which the couple and Walken drank at a restaurant and on the boat. Wood went to the master cabin during an argument between her husband and Walken. The last time Wagner saw his wife, she was fixing her hair at a bathroom vanity and she shut the door.

Wagner wrote that despite various theories about what led Wood to the water, which she feared, it was impossible to know what exactly happened.

"Nobody knows," he wrote. "There are only two possibilities; either she was trying to get away from the argument, or she was trying to tie the dinghy. But the bottom line is that nobody knows exactly what happened."

Later in the book, Wagner wrote, "Did I blame myself? If I had been there, I could have done something. But I wasn't there. I didn't see her."

He wrote that he has never returned to Catalina Island. The couple first married in 1957, and divorced six years later. They remarried in 1972.

Phone and email messages to Walken's publicist were not immediately returned. Attempts to contact Davern were unsuccessful.

Wood, who was nominated for three Oscars, starred in numerous movies, including "West Side Story" and "Rebel Without a Cause." 

Reuters and The Associated Press contributed to this report.