Isn't it also conceivable that those low-level staff wanted to sell books and could by going along with the story that he was there and killed himself. Or further that out of continued loyalty they furthered the story that he died. Or further that it made them way more important if the story that it was really Hitler and not his body double was told? To think we can ever know for sure about anything in the past is folly. Especially about famous ppl where money and ego get involved in telling the story.