Henri Bencolin is a fictional detective created by John Dickson Carr. He is Carr's first series detective, appearing in five "locked-room" and "impossible crime" mystery novels of the 1930s, and four short stories from an even earlier date. He is a juge d'instruction (examining magistrate) in the Paris judicial system. The books in which he appears are: * It Walks By Night (1930) * Castle Skull (1931 - not published in the UK until c. 1980) * The Lost Gallows (1931) * The Waxworks Murder (1932) * The Four False Weapons (1937)