Compared to the case of Poll Pilsworth, the account of Barnetby poisoner Mary Ann Milner presents no puzzle at all, and it also brings to light an exemplary piece of forensic investigation well before that line of work became a science. Barnetby is a beautiful and peaceful hamlet just beyond Brigg, these days en route to Humberside Airport. But in early Victorian times it was small and easily circumscribed: that is, everyone knew everyone else.
This aspect of life there made any kind of local misdeed something that was highly likely to be found out and fingers pointed in suspicion very soon after any suspicious action. Mary Milner, only twenty-seven-years-old, first killed her mother-inlaw and attempted to kill her husband. The latter survived, but it was easy to see why she might do it. She stood to gain plenty of money, paid from a burial club. For this, she was cleared, as there was no actual evidence to prove conclusively that she put the poison in the food. The old woman died quite quickly, but the husband survived, paralysed on one side of his body.
The medical men did find arsenic in the stomach of Mary’s mother-in-law, and there is a part jocular and rather sick story of the young woman buying the poison from Mr Percival in Barnetby. When he spoke in court, he recalled some pleasantries in talking to her, she referring to a rat problem and he commented that she did not look suicidal, so he should have no concerns in selling her the stuff. Perceval remembered that she had once had a dog who died through eating rat poison. Interestingly, the druggist also recommended that she take an antidote. He was clearly a careful man, who perhaps underneath the jocularity had some fears; his position was precarious in some ways if anything had come of this, because there was a high-level coverage of arsenic killings in the national and local press in this decade.