British criminal who was hanged for murdering her children and who may have poisoned as many as twenty-one people in total.
Her father plummeted to his death in a mine shaft in Murton, England when Mary Ann was eight years old.
Her murderous deeds were revealed after her stepson, Charles Cotton, died. The boy's doctor discovered that medical samples taken from the victim contained arsenic.
She was married three times and had close to a dozen children. All of her children, her husbands, her lover, her mother, and several children under her care died (most under mysterious circumstances).
She and fellow Englishwoman, Rosemary West, were both infamous serial killers.