NATALIE WOOD could have been killed by someone tossing her uncon­scious body overboard after a violent fight on a yacht, according to a new theory police are pursuing!

A source says police are consid­ering this shocking new theory after investigators re-examined the autopsy report of the beloved ac­tress, whose mysterious drowning decades ago continues to haunt Hollywood.

“Cops have taken a new look at Natalie Wood’s autopsy report and concluded specific urine levels in her bladder indicate that she may have already been unconscious when she hit the water,” a source close to the investigation told The ENQUIRER.

“How this could have been overlooked for so many years is outrageous, but it’s a new working theory – and it means her death in­volved foul play.”

Wood was 43 when she drowned on Nov. 29, 1981, while she and Wagner entertained her “Brain­storm” co-star Christopher Walken aboard their yacht “Splendour” off California’s Catalina Island.

Wagner has admitted arguing with Walken that night but claims Natalie left them and went to the yacht’s master cabin. Her body was later found in the water, clad in a flannel nightgown, socks and a red down jacket.

Authorities said the actress was legally drunk, and Wagner specu­lated that Natalie, annoyed by the sound of the yacht’s small dinghy hitting the side of the boat, went to tie it more securely and fell over­board.

At the time, officials ruled Nata­lie’s death an accident, and Wagner has always insisted that no foul play was involved. The yacht’s captain, Dennis Davern, has characterized it as an accident, but his comments

 have long fueled speculation about the tragedy.

In a 2009 book he co-authored, “Goodbye Natalie, Goodbye Splen­dour,” Davern specifically implicates Wagner, now 84, in her death, accus­ing the former “Hart to Hart” TV star of having a fight with his wife before she went missing off the boat. Davern also says Wagner delayed the search for Natalie after she disappeared.

Authorities reopened the investi­gation in 2011, and in July 2012 they took the unprecedented step of pub­licly changing her cause of death from “accidental drowning” to “drowning and other undetermined factors.”

The change in the death certificate “spurred investigators to continue to seek new evidence,” noted the source.

“Since that time, investigators have taken a fresh look at the autopsy report, which led them to the theory that Natalie was unconscious when she hit the wa­ter. It remains to be seen whether this can add up to anything sig­nificant enough for the district attorney’s office to determine there’s adequate evidence to file charges.”

In yet another twist, stunning new evidence has surfaced in the case, the source said.

“Police have also found new wit­nesses who support a key individual’s claims that have been made against Robert Wagner,” divulged the source about Davern’s claims.

“While Wagner is not officially a suspect, this should serve as a wake-up call to him and others that investigators are still determined to get justice for some in Natalie’s family who believe that her death wasn’t an accident.”

Wagner has fully cooperated with authorities since Natalie’s death, and police have said publicly that he’s not a suspect.