Natalie Wood Boat Captain Questions Homicide Investigation

As we previously reported, the L.A. County Sheriff's Department spokesman said investigators have found nothing to lead them to believe Natalie's mysterious death in 1981 was anything but an accident.

But a rep for Capt. Dennis Davern -- named Rick Kramer -- isn't convinced ... telling us, "We don't know that there's nothing new that's been found. That would be assuming that detectives in any situation report to the public on everything they uncover."

The rep added, "What [Dennis knows] is that for the first time ever there is a serious investigation by detectives in the homicide division into Natalie Woods' death, and that is very gratifying."