Uh, this happens to the rich & famous fairly often when a writer has a sordid story on someone.
The rich & famous buy the rights to the story. It is a shade away from blackmail - but perfectly legal.
Think about it. If a coworker knew you were having an affair and came to you and said he was going to write a story about an affair and was pretty sure anyone that read it would know it was you he was writing about - what he is doing is not illegal - and how much would you buy the story from him for?
My prediction: haldeman walks & writes a book about it.
Very interesting...
If so then Dave at least got a leg up on him and had the bastard thrown in jail.