Wilson was born around 1822 and worked as a nurse and housekeeper in Lincolnshire and London. She attended people in their final illnesses and was left money by several of them.
Between 1854 and 1862 seven people connected to her died: employers, a husband, and patients, among them Captain Peter Mawer, whose will she was left in, and her own husband. The deaths were attributed to natural causes at the time. She is thought to have used colchicine, an extract of meadow saffron, which produces symptoms indistinguishable from a violent gastric illness, and possibly arsenic.
She was arrested after Sarah Carnell, a woman she was nursing in London, was given a drink that burned her mouth, spat it out, and found that it had eaten into the bedclothes where it fell. Wilson was tried for the attempted murder and acquitted in 1862, the evidence being held insufficient. She was rearrested at once on the charge of murdering Maria Soames, a former landlady, and convicted.
She was hanged outside Newgate on October 20, 1862, before a crowd of some twenty thousand, the last public execution of a woman in London. She admitted nothing.
One conviction, one acquittal, and five deaths that were never charged: that is the range of one to seven in this roster. The figure of seven and the description of her as the greatest criminal of the age both come from the newspapers of 1862, and the case is a good example of how a Victorian poisoning count was assembled after the fact from a person's employment history.