Turns out back in 1924 a reporter named Edgar Wallace wrote an article discussing the murder by poison committed in 1921 by one Herbert Armstrong in Wales. That's Herbert Rowse Armstrong. The article is entitled Herbert Armstrong - Poisoner.
Here's the introduction.
THE crime of Herbert Armstrong, M.A., the Welsh solicitor, who murdered his wife by administering arsenic, was especially mean and contemptible. Love affairs entangled his life and flattered his vanity, and it is probable that a hatred of his dull and respectable existence in a tiny village was one of the motives for his terrible deed. This story of Armstrong is told by Mr. Edgar Wallace, who attended the trial, and on behalf of a newspaper syndicate offered the convicted man £5,000 for his confession—an offer which was refused.