John Dickson Carr : A Guest in the House, 1940 ; aka "The Incautious Burglar" ( in The Men Who Explained Miracles, 1963)

John Dickson Carr after the war, went through a period of weariness.
He had done his best, working with the BBC during the war, creating subjects, the most varied, for radio plays, and this overwork probably exhausted his mental energies, or at least reduced them, if it is true that after the war he often elaborated ideas previously had. However, even during the war he had to go to savings, if it is true that a story served as a basis for a novel. This is the case of A Guest in the House (published in The Strand, in October 1940), and then republished as The Incautious Burglar "(in The Men Who Explained Miracles, 1963) from which Carr drew the basic idea for The Gilded Man of 1942. Marcus Hunt is a collector of famous paintings. In his villa he owns two Rembrandts and a Van Dyck, but for a decision that only he knows, and which is inexplicable even to his daughter, instead of letting them stay where they were positioned, that is on the top floor, he even moved them downstairs, like if you want to encourage their theft.

One evening there are two friends of Hunt gathered together: one is Arthur Rolfe, an antique dealer and art dealer; the other is Derek Henderson, an art critic. They played poker with two other people who left, and now they are there and inevitably talk to each other. At one point, Henderson doing a solitaire, draws an ace of spades; then he takes another. More than eloquent sign of death. But nobody takes notice of it. That night happens the imponderable but everyone expected that it could happen: a thief, who has been waiting for a while outside the villa, after seeing that there is no movement on the ground floor, begins to cut the window glass with a diamond, he enters the room, goes to the wall where the most valuable Rembrandt is displayed, and begins to detach it, not realizing that in the room he’s not alone: ​​there is someone else in the shadow that is observing him. A short time later a deafening noise breaks the silence from the floor below. The first to come and Lew Cutler, another guest of the house, of which little is known and that Hunt's daughter suspects to be someone under false identity. Beneath a mountain of silver tea-service items, including a teapot, and a centerpiece with scattered fruit on the floor, there's a masked man, that for the very blood-smeared clothes, seems unequivocally dead. Especially since the fruit knife, very sharp,  is smeared with blood and lies next to the thief's body.

Harriet Davis, the daughter of Marcus Hunt, arrives. Cutler, acting not as a guest but as a landlord, sends his daughter to his father. Hunt the others in dribs, but Hunt is not there. And not even in his room. The suspect becomes certain when Cutler, who is a sergeant from C.I.D. of Scotland Yard, unmasks the thief and stands before Marcus Hunt. And he must understand how Hunt was killed and why Hunt was disguised as a thief. As if he wanted to steal his paintings. But why? Cutler reveals that he had been sent there because his superior suspected that Hunt wanted to play the old game, to steal the insurance on his canvases. Only then he realized, questioning the girl, that there was no insurance on the paintings. Why then would Hunt try to steal his paintings? And who and why had he killed him?
The police gropes and eventually someone comes up with the idea of turning to Dr. Fell.

Fell must reason on the basis of the indications that are exposed to him:
several pieces of silver service placed on the sideboard had scratches as if they had been piled up to form a pyramid and then rolled down;
Hunt was killed by a knife that reached his heart, inflicted with a knife with a very thin blade, but such that the wound was difficult to find;
the abundance of blood found on clothes.
"The old woman with the bonnet" by Rembrandt was found under Hunt's body. So it was not stolen.
Why murder? Why the attempted theft of uninsured and authentic paintings? Who killed the fake thief?
Fell will find out after talking to all suspects on a sunny summer afternoon, after examining them and weighing their clothes. And the means to find out will be, forcing the suspects to take a swim in the pool.
This is a Fell hurried that appears when the crime has already been consummated. He drinks his usual pints of beer, but he does not wear black suits: he usually appears dressed in a cape and with dark-colored clothes, while here he is clad in a white linen suit. I'll point out the comparison that seems more appropriate to me with another carrian character: Merrivale, who we find most often dressed in white. Why do I dwell on this particular of no importance? Because it would seem to me to have drawn Fell in the manner of Merrivale, it could mean that when Carr was writing the story, he may have already thought about using the story as a basis for a novel, with Merrivale, which came about two years later with The Gilded Man.

However, the interesting thing is not so much this as how the victim dies.
And even all that human blood, unnatural bearing in mind that the wound was not even seen, is an excellent indication. The wound could not be seen. The used knife was extremely thin. Already.
We are faced with an umpteenth variation of death caused by a very thin weapon.
In a novel, always with Fell, we witness an event caused by a weapon and a wound like that: there, however, it is not so much the absence of blood to be remarked (also) but above all the fact that the victim does not become aware of it or otherwise, he benefited from the nature of the wound in her drama. The novel is a famous novel with Doctor Fell: He Who Whispers, which is from 1946. Two stories with Fell presenting two effects of the same modus agendi: a stab wound with a very thin blade, causes a blood spill extremely narrow and death is not sudden. And then all the blood that stained the victim's clothes, where did it come from? Evidently, even  who had hit the victim were hurt. So here's why Fell asks everyone to take a bath in the pool: bercause only with that way the killer would have been unmasked. And in fact, he is unmasked.

The idea behind the death of Hunt, who is not the real thief is based on a true fact: the murder of Empress Elisabeth of Bavaria, the famous "Sissy" who became a consort of Emperor Franz Joseph, who died in 1898 following the attack of an anarchist. This famous death was resumed in many masterpieces of the locked room: before being used by Carr in He Who Whispers, and to be remembered in In Spite of Thunder, had been used elsewhere and Lacourbe even attributes the origin of the idea of ​​the locked room in Le Mystère de la chambre jaune to the murder of the Empress. Another French writer used it also: in Thérèse et Germaine, the third of the eight stories by Maurice Leblanc contained in the collection Les Huit Coups de l'horloge, of 1923 (even though the first three stories were serialized in the daily Excelsior in December 1922.) Another novel that presents it, is Envious Casca by Georgette Heyer, which is from 1941, a year after the publication of Carr's story, which re-presents the same modus agendi by He Who Whispers, which is later (the victim does not notice the severity of the stab, until he dies).

Another extraordinary story by Carr that satisfies all the questions with a simply perfect solution.

Pietro De Palma