After private funeral services attended by only her family and closest friends, Natalie Wood will be buried tomorrow, and she may take with her to the grave the mystery surrounding the last hours of her life.

A sheriff's homicide detective today refuted coroner's statements suggesting that actors Robert Wagner and Christopher Walken were arguing heatedly aboard an anchored yacht early Sunday when Wood, Wagner's wife, drowned.

"I don't know where the coroner got that information," said Los Angeles County investigator Roy Hamilton. "We talked to Wagner and Walken, and there was no indication that there was any argument.

"I think he Los Angeles County coroner Thomas T. Noguchi was juicing it up a little bit," Hamilton added.

Indeed, the coroner's office today appeared to be soft-pedaling the conclusions that emerged during yesterday's news conference on the death of the 43-year-old actress, whose body was found floating off Blue Cavern Point, Santa Catalina Island, Sunday morning.

"We think 'argument' might be too strong a word," assistant coroner Richard Wilson said today. "It might have been an animated conversation . . . heated conversation . . . a lot of conversation over a number of hours."

The coroner's official findings -- that Wood was "slightly intoxicated," that she drowned accidentally while trying to leave her yacht, that Wagner and Walken, had been arguing -- do not answer these questions:

* What drove her from the yacht Splendour around midnight, after she had undressed for the night?

* Why did she throw a parka-type jacket over her nightgown and, despite her admitted terror of "deep water, dark water, the sea," untie an inflatable dinghy in the middle of a cold, dark night, and try to sail away, alone?

* Where was she headed? What was in her mind? And why did the arguments between Wagner and Walken have anything to do with a departure that ended in a tragic, needless death?

The New York Daily News learned today that neither the coroner's office nor the sheriff's investigators intend to probe Wood's state of mind, contending "it has no bearing" on the case now that officials are satisfied completely that the death was accidental.

When Noguchi was asked at his press conference yesterday about Wood's state of mind, he answered that it might be "important to find out what thoughts she had by psychological autopsy."

Deputy Sheriff Allan Senkow said today that "no further criminal investigation" is scheduled in the Wood death because both the coroner's office and the sheriff's homicide investigators are convinced the actress' drowning was accidental, and there was no evidence of foul play.

Attorney Paul Ziffren, lawyer and friend of the Wagners', has been at their home every day since the tragedy and described Wagner as "devastated."

Ziffren, when asked if he knew what the men were arguing about or why Wood left the yacht, said: "I consider it all irrelevant."

None of Wagner's friends would reveal the time or place of the funeral services, in accordance with his wishes to keep it "very private."