Working on my family tree, I discovered on my mother's side, a genuine female serial killer! One of the infamous Victorian Black Witches, she dispatched her husband and children with arsenic! She was eventually caught after one of her boys survived and testified against her. The bodies were exhumed and she was hung in the town square of Lewes, Sussex.
The story, which featured original gruesome murder reports in the London Times, was picked up by the paper, after being published on Atlas Obscura.