Reading progress update: I've read 147 out of 272 pages.

Ok, it all depends on how this story will conclude now, but so far I can see this story might be an inofficial addition to the Summer of Sherlock bookshelf.
I'll leave it at that for now.
Now back to the book because I really want to know how this ends!
I have hunches, of course, but this is a Golden Age mystery ... even if it is set in the time that the "East Wind" has arrived, so I expect twists.