There are people that think that Boothe wasn't the shooter and that it was a Cuban plot - another shooter was on the grassy knoll and shot Lincoln through an open window.
I've done intensive research and I think the killer was his wife, Mary. She had been known to indulge in a little 'free love' with local slaves and she didn't want her husband fucking up that arrangement.

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there's probably a ginormous list of directors / producers / crew who were directly or indirectly responsible for stuntmen deaths, and sometimes actors and crew as well. vic morrow, brandon lee, and an army of unknowns...