I've recently completed an Agatha Christie-style whodunit titled "The Wych Elm Murders.". (can currently be found on Kindle Scout - amzn.to/2kQhBxt). It features a Private Investigator, Al Street, However, there is a subsidiary character, Miss Mary Turnbull who is roughly based upon Miss Marple. A deviation from the original style is the inclusion of what might be termed, adult material. But there are the usual, 'red-herrings' and misdirection. It takes place in a country house in The New Forest. The only other thing I can say about it is that the butler didn't do it! are
My question is, how popular are such stories today when much of what we read in the genre are stories that drag us along a well-trodden path; a path that requires little thought. The whole purpose of an Agatha Christie novel was to engage; to think; to try to make sense of the clues. Most of all, to try to guess whodunit!