The Market Basing Mystery, by Agatha Christie (epub/Kindle/pdf)
At Japp’s suggestion, Poirot and Hastings join him for the weekend in the small countryside town of Market Basing. While enjoying Sunday breakfast, the three are interrupted by the local constable, who requests Japp's help. Walter Protheroe, the reclusive owner of a local large mansion, has been found dead in his dilapidated house, supposedly by suicide. Or is it?