The Four Just Men
Warn Ramon that the Four do not go outside their promise. If they have threatened to kill in a certain manner at a certain time they will be punctual. We have proof of this characteristic. After Anderson's death small memorandum book was discovered outside window of room evidently dropped. Book was empty save for three pages, which were filled with neatly written memoranda headed 'Six methods of execution'. It was initialled 'C.' (third letter in alphabet). Warn Ramon against following: drinking coffee in any form, opening letters or parcels, using soap that has not been manufactured under eye of trustworthy agent, sitting in any room other than that occupied day and night by police officer. Examine his bedroom; see if there is any method by which heavy gases can be introduced. We are sending two men by 'Lucania' to watch.
The detective finished reading. 'Watch' was not the last word in the original message, as he knew. There had been an ominous postscript, Afraid they will arrive too late.
Ha! That was fun. Granted the premise is ridiculous, the plot has massive holes in it, the writing is tainted with all of the hallmarks of its time, and the solution was drawn out of a hat at the end, but it was fun to read this.
In a way, this was also an interesting book to show up differences in how our understanding of the term vigilante justice has changed since 1905, when this was written, and how our understanding of the particular "justice" exerted in this story may have changed, too.
Or has it? I mean, I read an article the other day discussing an apparent rise in people believing that it is ok or even justified to send death threats to politicians. Nothing new there, of course, even if it is hitting home hard when this is a reality for friends in that career path.
However, since the murder of Jo Cox over something as trivial (in the greater picture of things) as her stance on Brexit this issue has been a very public one.
So, yes, there were angles to the story that were a lot more intriguing than the plot itself, which fell apart even on the basic premise that a bill could be stopped becoming law just by killing of a single minister. It's just not quite how it works. Thankfully.