The most interesting thing about Marie Besnard might not be that she was accused of poisoning about a dozen people. It's that she got away with it -- and got wealthier with each murder.
Sally Basset was an enslaved woman who was executed in 1730 for allegedly attempting to poison her granddaughter’s enslavers. She is known throughout Bermudian folklore, where she is, to many, a hero.
Giulia Tofana was an Italian apothecary known for her beauty, her secrecy and her poisonous proclivities. If the numbers are all to be believed, she may be the most successful serial killer you’ve never heard of.