locked room mystery

The locked-room mystery is a subgenre of detective fiction in which a crime—almost always murder—is committed under circumstances under which it was seemingly impossible for the perpetrator to commit the crime and/or evade detection in the course of getting in and out of the crime scene. The crime in question typically involves a crime scene with no indication as to how the intruder could have entered or left, i.e., a locked room. Following other conventions of classic detective fiction, the reader is normally presented with the puzzle and all of the clues, and is encouraged to solve the mystery before the solution is revealed in a dramatic climax.