They have no witnesses. They have no case. With this blunt observation, Mariann Colby—an attractive, church-going Shaker Heights, Ohio, mother and housewife—bet a defense psychiatrist that she would not be convicted of murder. A lack of witnesses was not the only problem that would confront the State of Ohio in 1966, which would seek to prosecute her for shooting to death Cremer Young Jr., her son’s nine-year-old playmate: Colby had deftly cleaned up after herself by hiding the child’s body miles from her home and concealing the weapon.

Nicknamed “the Blonde Borgia,” Anna Marie Hahn was a cold-blooded serial killer who preyed on the elderly in Cincinnati’s Over-the-Rhine district in the 1930s. When the State of Ohio strapped its first woman into the electric chair, Hahn gained a place in the annals of crime as the nation’s first female serial killer to be executed in the chair.