some time back I met a retired LA cop out near Death Valley. He claimed he stopped a car for driving erratically driven by Peter Lawford with Bobby Kennedy as a passenger. Kennedy was staying at the Beverly Hills hotel (the pink one). Anyway he cut them loose only to find out a bit later that MM "died" that night. He then went to the hotel and got either the registration records or copies of same showing Kennedy as a tenant at the hotel that night (Bobby was officially in San Francisco that night). He put them in the trunk of his car. Later he was involved in a shootout and one of the PDs towed his car and the Kennedy proof disappeard from his trunk...
He wrote a book about this and other corruption. I've a signed copy somewhere. Until I find that I probably won't be able to remember his name.