''Night's Cloak'' by E. R. Punshon (d. 1956), public domain. The story follows Detective Inspector Bobby Owen as he untangles a complex web of murder, radical political movements, and a sinister swindle executed by a millionaire.
The narrative famously features a baffling study murder and a suspect with an almost impossible alibi. Notable literary figures like Dorothy L. Sayers have praised the clever plotting and "distinction" found in Punshon's writing. However, the book's heavily intricate and detailed style is also known to offer a challenging and exhaustive puzzle for readers.