LOS ANGELES (CBS) — The Los Angeles Coroner’s office has decided to change Natalie Wood’s cause of death from accidental drowning to “undetermined.”

READ MORE: Strike Averted: IATSE And AMPTP Have 'Basic Contract' Agreement, Per Officials With The Theatrical Stage Employees Union

Wood — then 43 — drowned nearly 31 years ago off the coast of Catalina Island.

Her death was shrouded in mystery almost from the start.

According to TMZ, the death certificate will now be changed from “accident” to “undetermined.”

The Oscar-nominated Wood, her then husband actor Robert Wagner and actor Christopher Walken took Wagner’s boat, The Splendour, out for a weekend excursion.

The yacht’s captain, Dennis Davern, asked for the case to be re-opened last year. He said Wagner was responsible for Wood’s drowning.

Davern said that Wagner and Wood got into a heated argument. After Wood fell into the water after a heavy night of drinking at a restaurant on the island (she also had been taking several prescription pills) Davern says Wagner refused to look for her. That statement contradicted what he told police immediately after the drowning.

On an appearance on “The Today Show,” Davern said, “It was a matter of ‘We’re not going to look too hard, we’re not going to turn on the search light, we’re not going to notify anybody right at the moment.'”

READ MORE: Taylor's Blunder, Other Missed Chances Put LA In NLCS Hole

Davern added, “I made some terrible decisions and mistakes. I did lie on a report years ago. I made mistakes by not telling the honest truth in a police report.”

When Davern was asked if Wagner was “responsible” for Wood’s death, Davern said, “Yes I would say so.”

The actress’s sister, Lana Wood, has also publicly questioned the quick investigation and official ruling. She told TMZ that she never believed Wagner’s version of the events that led to her sister’s death. She told KCAL9 last year, “I don’t think ‘I’m sorry for your loss Mr. Wagner’ is an investigation.”

Through a spokesperson last year, Wagner said, “[The family] 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.”

According to TMZ, members of Wood’s family said detectives from the Coroner’s office made them aware of the change earlier today.

The report also said detectives told Wood’s family the change was made in part “because some of the bruises on her body were inconsistent with death by accident.”

CBS2 and KCAL9 reporter Bobby Kaple spoke to KCAL9 legal analyst Steve Meister Friday and asked what this change in the cause of death means.

Said Meister, “It means that this case is re-opened and it will stay open indefinitely until they can figure out conclusively what happened.”

MORE NEWS: Karen Bass Officially Kicks Off Her Run For Mayor Of Los Angeles At Saturday Event

He added, “And if you are a person who has been under investigation, you don’t like that this has been changed to undetermined or unresolved because that means it’s not over.”