The Hollow Man (The Three Coffins) by John Dickson Carr

A man is killed in a locked study surrounded by undisturbed snow. The killer vanishes, and leaves no footprints. Shortly thereafter another victim is killed, this time in front of witnesses on a snow covered street. Yet again, the murderer is nowhere to be found, and only the victim's footprints lead to the body...

The Hollow Man (published in the U.S. as "The Three Coffins") is one of JDC's most critically acclaimed works, and in 1981 was voted the best locked room mystery of all time by a panel of mystery authors. The plot follows Dr. Gideon Fell as he assists the police in uncovering the truth behind two interconnected impossible crimes:

1. Professor Charles Grimaud was killed in his study by a mysterious figure. The intruder is seen entering the room, then vanishes in to thin air. Fell and co are quick to inspect the scene, but find no possible route of escape.
2. The illusionist Pierre Fley is shot from point blank range on a snow covered street a few minutes from the scene of Grimaud's death. Witnesses at either end of the street confirm that there was no-one around Fley at the time of shooting, but the angle of the gunshot wound means it cannot have been self-inflicted.

The Locked Room Lecture

If the body was found alone in a locked room, how can the murderer have escaped? The question at the centre of the classic locked room mystery conundrum has fascinated and inspired authors for generations.

John Dickson Carr, in his widely acclaimed novel The Hollow Man (published in the US as "The Three Coffins") attempted to provide a comprehensive list of possible methods (while, ingeniously, challenging the reader with his own locked room mystery that seems to fit none of his prescribed solutions).

An entire chapter is dedicated to a discussion between Dr. Gideon Fell and his friends on the possible solutions to locked room mysteries.

"...if you're going to analyze impossible situations,' interrupted Pettis, 'why discuss detective fiction?'

'Because,' said the doctor, frankly, 'we're in a detective story, and we don't fool the reader by pretending we're not. Let's not invent elaborate excuses to drag in a discussion of detective stories. Let's candidly glory in the noblest pursuits possible to characters in a book."

The Locked Room Lecture

The following excerpts from the book details Fell's various explanations to the locked room conundrum:

"1. It is not murder, but a series of coincidences ending in an accident which looks like murder. At an earlier time, before the room was locked, there has been a robbery, an attack, a wound, or a breaking of furniture which suggests a murder struggle. Later the victim is either accidentally killed or stunned in a locked room, and all these incidents are assumed to have taken place at the same time. In this case the means of death is usually a crack on the head–presumably by a bludgeon, but really from some piece of furniture. It may be from the corner of a table or the sharp edge of a chair, but the most popular object is an iron fender The murderous fender, by the way, has been killing people in a way that looks like murder ever since Sherlock Holmes' adventure with the Crooked Man. The most thoroughly satisfying solution of this type of plot, which includes a murderer, is in Gaston Leroux's The Mystery of the Yellow Room–the best detective tale ever written.