The Plague Court Murders by Carter Dickson

" I want you to spend the night at a haunted house" Ken Blake was approached by his friend Dean Halliday at their club with this strange request. Blake, who had been a bit bored with life lately, immediately accepted this challenge. Since both Blake and Halliday were novices at ghost hunting, Blake requested that he bring along an expert on the subject,  Detective Inspector Masters from Scotland Yard in an unofficial position because  Masters had quite a bit of experience in exposing bogus mediums in the past.

There is a lengthy back story involved in the episode which will follow and most of it deals with  Louis Playge  who was the common Hangman of Tyburn in the years 1663 - 65. It was for him that Plague Court was named. Curiously a dagger that was supposed to have belonged to Playge had recently been stolen from the London Museum.

Blake, Halliday, and Masters went to Plague Court in the evening. In this decaying building, they joined two women who were already there. There was young Marion Latimer and a much older woman, Lady Anne Benning, who was Dean Halliday's aunt. Also present were Marion's brother, Ted Latimer, and Major Featherton. A medium, Mr. Darworth, was there that evening to exorcise the evil spirit which haunted the house. Darworth had brought with him the boy Joseph who was able to receive spirits, but not to exorcise them. Darworth was now locked in a small house on the property. He had arranged a bell which would be heard in the house if anything happened to him.

That evening, Darworth was murdered in the locked house. Some said that they heard the bell ring and others did not. Masters had grown very worried about Darworth, and insisted they break down the door which the men did with great difficulty. They found Darworth who had been stabbed lying before the fireplace in a locked room with no footprints in the mud outside to show that anyone had entered the building.

Now entered Sir Henry Merrivale whose assistance was requested by both Blake and Major Featherton.  Sir Henry had been head of the British Counter-Espionage during the war, and was still associated with the war department. Sir Henry was a large, indeed very large, man who had been sitting in his office "fixing his mind in the coruscations of the infinite". He was very interested in taking on the mystery of the Plague Court murder. Soon another gruesome murder would occur to further complicate the solution of the crime. No crime was too difficult for HM, and he found the murderer and explained how it was done.

This is the first of many locked room mysteries which were written by John Dickson Carr using the pen name Carter Dickson in 1934. Sir Henry Merrivale is a master of solving this type of murder, and I have always found his exploits fascinating.