19. Mary Ann Cotton
When Mary Ann found out that she would receive payouts for the death of a family member, she wasted no time. She murdered 21 people via arsenic poisoning, 12 of which were her own children. She also killed several husbands and even her own mother just to make a quick buck.
18. Leonarda Cianciulli
Cianciulli was an Italian woman who killed three women between 1939 and 1940. Although that is a low body count, what she did with them was horrifying. Cianciulli used the remains of the bodies to make soaps that she would later bathe with. In addition to soap, she used dried blood from the victims in her tea cakes that she served to friends when they would visit. She also claimed that she enjoyed eating them.

When Mary Ann found out that she would receive payouts for the death of a family member, she wasted no time. She murdered 21 people via arsenic poisoning, 12 of which were her own children. She also killed several husbands and even her own mother just to make a quick buck.
18. Leonarda Cianciulli

Cianciulli was an Italian woman who killed three women between 1939 and 1940. Although that is a low body count, what she did with them was horrifying. Cianciulli used the remains of the bodies to make soaps that she would later bathe with. In addition to soap, she used dried blood from the victims in her tea cakes that she served to friends when they would visit. She also claimed that she enjoyed eating them.