Mary Ann Cotton
Mary Ann Cotton is infamously known as one of the United Kingdoms’ first prolific female serial killers. She was ultimately convicted and subsequently hanged for the murder of her stepson – Charles Edward Cotton. However it is alleged she may have had up to a whopping 21 victims, including, but not limited to, 3 of her husbands and 11 of her children / stepchildren. She was partial to killing her victims with arsenic, which was common in those times, but was suppose to be used on vermin, not humans!
During her trial, Mary Ann’s defense tried to convince the jury that the arsenic had come from the dye in the wallpaper (as was common in those days) and inhaled by Charles. Ultimately the jury failed to believe her excuses and found her guilty. Mary Ann Cotton, still pleading her innocence until the end, was hung on the 24th March 1973 for the murder of Charles Cotton. However, the hanging was botched resulting in a slower, more painful death from strangulation rather than a broken neck due to the rope being rigged wrongly. Whether the botched hanging was deliberate or not is unknown.