Police say the actor Robert Wagner is a "person of interest" in a police investigation into the mysterious death of his wife Natalie Wood in 1981.

The body of Wood, who was an acclaimed actress and had been nominated for three Academy Awards, was found floating in the water of California's Catalina Island after a night of drinking on a yacht which also had Christopher Walken on board.

The case was reopened in 2011 after an initial investigation ruled that it was an accident.

But Los Angeles County sheriff's lieutenant John Corina told CBS Wagner had not revealed everything about that Thanksgiving weekend night.

"As we've investigated the case over the last six years, I think he's more of a person of interest now. I mean, we know now that he was the last person to be with Natalie before she disappeared."

In response to the question of whether he thought Wood had been murdered, Cornia said: "I think it's suspicious enough to make us think that something happened."

A sheriff's department spokeswoman later said there was nothing new with the case.

There have been differing reports of what happened on the night Wood disappeared. All three had been drinking heavily and Wagner wrote in his memoir that he had argued with Walken, who went to bed. When Wagner himself to be, he saw that his wife and a dinghy attached to the yacht were missing.

But police say two new witnesses have corroborated accounts of a fight between Wagner and Wood on the night she disappeared and that the actress was the victim of an assault, the BBC reported. The post-mortem report said Wood had bruises on her body and arms as well as a facial abrasion on her left cheek.

Wagner has denied any involvement in his wife's death and no charges have been filed. His publicist, Alan Nierob, did not comment, ABC reported.