Toward the end of January 1815 she entered the service of tradesman Orlibar Turner of 68 Chancery Lane, London, in the capacity of cook.
The case came before the Old Bailey on 11 April 1815, when Fenning was charged with feloniously administering arsenic to the three Turners with intent to murder them.
Roger Gadsden, an apprentice of Turner, had eaten a piece of dumpling after dinner, though Fenning had strongly advised him not to touch it, and he had also fallen ill. Fenning pleaded not guilty and urged that she herself had eaten of the dumplings, a piece of testimony which was corroborated by Turner's mother, who said that she had been sent for, and on arrival had found the prisoner very sick.
Popular opinion was largely in favour of Fenning's innocence, and every effort was made by her friends and others to procure a remission of the sentence.
At her funeral, which took place five days later at St George the Martyr, Bloomsbury, the pall was accompanied by six girls dressed in white, and as many as 10,000 persons took part in the procession which was formed to the grave.
He wrote: "All the masters and mistresses of families, who credulity or idleness rendered them proper subjects for alarums, were excessively devoted to the vociferous execration of the wickedness of servants.
In an 1829 publication, Smith highlighted an article in the Morning Journal from March that year which details the death of Robert Gregson Turner in Ipswich Workhouse after he confessed his guilt for the crime for which Fenning was hanged.
[8] Author Sandra Hempel, who specialises in topics of health, has highlighted the Fenning case as one which led to the development and advancement of forensic evidence as a means of determining guilt in murder trials.