This story was serialised in the Dundee Weekly News in 1878, and then the Morpeth Herald between September 1881 and March 1882. I haven’t found any evidence of it being published elsewhere. It was subtitled “A Story of the Secret Police,” which might have meant something else at the time, but now appears misleading, as it merely refers to the plain-clothes detective force.
This version is a transcription of the episodes from the Morpeth Herald, obtained from the British Newspaper Archive. There may be mistakes, but there are probably fewer than as originally printed, when even the surnames of characters weren’t spelled consistently.
There is another quirk with this publication: chapters 19 and 23 do not exist. None of the story is missing, but those two chapter numbers were inadvertently skipped.