Though not widely known, Mary Cowan was one of the most cold-blooded and deadly female serial killers of the 19th century. Her willingness to murder her husbands and children without a seeming shred of remorse makes her a fascinating case study.
Mary Knight was born in Plymouth, Maine, in 1863. Her father, Johnathan Knight, was a Civil War veteran. The Knight family lived in a rural, quiet area of Maine. Mary grew up in the family home, where she remained until she married Willis Bean, a farmer who lived in the neighboring town of Dixmont.
