UPDATED Friday, 11:08 a.m.
At a press conference, Lt. John Corina said that the department had decided to take another look at Wood's death because it had received new information that was "substantial" and "credible" enough to re-open the investigation.
"Several sources … have come forward with additional information, and we found it credible enough to take another look at the case," Corina said.
He would not elaborate on who the sources are but said they have not yet talked to the captain of Wagner's yacht, Dennis Davern.
Read also: Natalie Wood's Yacht Captain: I Was Loaded When She Disappeared
During an interview on the "Today" show Friday, Davern told NBC's David Gregory that he had lied at the time to investigators about the circumstances behind Wood's death, and said that Wagner was "responsible." Asked if the sheriff's department would follow up with Davern regarding that claim, Corina said, "We'll end up probably talking to the captain sooner or later."
At the time of the original investigation, Wood's drowning was ruled an accidental death, and Corina said that ruling will remain unless other evidence proves to the contrary.
"If our investigation, at the end of it, points to something else, then we'll address that," he said. "Until we find something that says it isn't, it's still an accidental drowning."
Corina also told reporters that, since the announcement that the department was re-opening the investigation, "people are coming forward and want to talk to us." Asked if the department is concerned that people were coming forward because of the timing — Wood died nearly 30 years ago to the day, on Nov. 29, 1981 — Corina said no.
"We're not concerned with the anniversary date," Corina said, allowing, "it might have jarred some people's memories since it's been in the media."
As to whether investigators will take another look at the yacht, Splendour, that Wood was aboard the night day she died, Corina asserted, "We'll go wherever the investigation is going to take us." He also affirmed that the department will use new technology that wasn't available at the time of the 1981 death if it makes sense to do so.
UPDATED, Friday, 9:13 a.m.
Robert Wagner is responsible for the death of Natalie Wood, the captain who sailed with the couple on the day she drowned told NBC’s “Today” show on Friday morning, a day after the Los Angeles County sheriff’s department reopened the investigation.
In an interview with NBC's David Gregory, the captain Dennis Davern said he had heard an argument between Wagner and actor Christopher Walken — who was also on the yacht — which was followed by a thump.
The argument between the two actors was known at the time. It was theorized then that Wood tried to leave the yacht that the trio was staying on, or else was trying to secure a rubber dinghy that was banging against the hull of the boat, when she drowned.
"Yes," Davern replied.
"Like I said, that's going to be up to the investigators to decide," he said.
Wagner's spokesperson said Thursday that the actor welcomes the Sheriff's investigation, as long as it springs from valid sources. A statement issued by his publicist also suggests that the new claims could be the result of opportunism.
"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 L.A. County Sheriff’s Department 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," the statement reads.
Wagner's camp will very likely take issue with Davern's claims. Davern is the co-author of a 2009 book, "Goodbye Natalie, Goodbye Splendour" (the title derives from the name of the yacht, Splendour). The book seems to contest the version of events laid out in Wagner's own memoir, "Pieces of My Heart," which was published shortly before Davern's tome.
"In his recent best-selling memoir 'Pieces of My Heart,' Robert Wagner told his version of what happened on the yacht Splendour on the night his wife died. But is Wagner's version accurate? Who knows the truth?" a blurb for the book reads. "'Goodbye Natalie, Goodbye Splendour' is the result of a decades-long investigation by journalist Marti Rulli and Dennis Davern, Natalie's friend, confidant, and captain of the Splendour on that controversial night."
During the "Today" interview, Davern told Gregory that he'd been trying to give people this information for years but "there wasn't really anyone listening until now."
Davern also said he lied to investigators at the time about the circumstances surrounding the "West Side Story" star's death.
"I made some terrible decisions and mistakes," Davern said.
Watch Davern's interview in the video:
Davern's interview aired a day after the Los Angeles County Sheriff's Department announced that they are re-opening the investigation on Wood's death, saying that individuals had come forward with new information.
"Recently Sheriff’s Homicide Investigators were contacted by persons who stated they had additional information about the Natalie Wood Wagner drowning," a statement issued by the department on Thursday reads. "Due to the additional information, Sheriff’s Homicide Bureau has decided to take another look at the case."
The Sheriff's Department will hold a press conference on the re-opening of the case Friday morning at 11 a.m.
Wood drowned Nov. 29, 1981, at the age of 43. The three-time Oscar nominee had gone on a boat trip to Catalina Island with Wagner and actor Christopher Walken, her co-star in the then-unfinished "Brainstorm" (pictured left). The coroner's department determined that Wood had consumed numerous glasses of wine before her death.