A few years ago some documentary presented the story that Charles Lindbergh killed his own child and faked the kidnapping.
More likely true than not.
There are actually several books asserting that. In my opinion, none of them is a smoking gun - but - taken all together they really make you wonder. I don't think he killed the child on purpose, but as part of a terrible prank on his wife and their housekeeper, it is plausible.