Armstrong was tried at the Shire Hall, Hereford, for the murder of his wife; if he had been acquitted of that there was another charge on the indictment accusing him of the attempted murder of Mr. Martin, a fellow solicitor and business rival.
There is support for the view that if the exhumation of Mrs. Armstrong's body, ten months after its burial, had not revealed the presence of arsenic, and led to Armstrong's conviction, other graves would have been disturbed and other tragedies brought to light. This was the last murder case tried by Lord Darling, the greatest criminal judge of his day.