The Hollywood Rumor:
You can already see why this incident cast such a long shadow. Wood's fear of water made the story of her going out in a dinghy seem implausible, the bruises covering her body even moreso. With both Wagner and Walken saying they had no idea what happened, the rumor mill was free to make up whatever scenario sounded right -- that Wagner had assaulted her and thrown her overboard, that she fell off during an argument, that it was just an accident, but one that cast everyone in a poor light, so they claimed she disappeared instead. If you want to believe the worst, you can take your pick.
While the police didn't blame Wagner, Lana Wood, Natalie's sister, was not convinced. When the boat's captain, Dennis Davern, came forward around the 30th anniversary of the death, both he and Wood stirred up the embers of the long-buried case. Davern outright accused Wagner of shoving Wood overboard. Police investigated, but came to the same conclusions they did years before, that it was an accident. Though it is a bit odd that they changed her death certificate from "accidental drowning" to "undetermined."