How doesn't he know what happened to Natalie Wood?

Always good for actors to stay relevant, they hate it when the phone stops ringing.

How doesn't he know? I thought the story was, they were all partying really hard on the boat. I can see myself passing out in a chair or on a couch, wake up next morning not remembering anything.

she was drunk and mixing it with meds.

He did say what happened. Every person on that boat cooperated with the police.

I've been on a small yacht with several people. It's possible to be in one compartment and have no idea what's going on in another compartment or on deck. And I wasn't even drunk.

They were drinking and doing who knows what else. He and the rest of the group passed out. Hence they didn't see Wood stumble out of the room nor did they hear her fall into the water.

That is considering the whole story is true. There is some speculation that Wood faked her own death.