I have vague memories of a tale about a female serial killer from the Great Depression era. She married well, insured heavily then drugged her husband before setting fire to their house. After a suitable period of grief she upped sticks to another state and did just the same all over again.
She married and killed about 15 times before she was caught, tried, sentenced and (as I recall) executed.
But that’s not what I remember the most. What makes this story still echo in my mind is that she sat calmly and watched the burnings. Every. Single. Time.