Father Jourdain now wore a thin light-coloured suit, a white shirt and a black tie. The change in his appearance was quite startling; it was as if a stranger had walked in.

“I really don’t feel,” he said, “that the mortification of a dog collar in the tropics is required of me. I shall put it on for dinner, and on Sunday I shall sweat in my decent cassock. The sight of you two in your gents’ tropical suitings was too much for me. I bought this in Las Palmas and in happier circumstances would get a great deal of pleasure out of wearing it.”

They sat down and looked at Alleyn with an air of expectancy. It occurred to him that however sincerely they might deplore the presence of a homicidal monster as their fellow traveller they were nevertheless stimulated in a way that was not entirely unpleasurable. They were both, he thought, energetic inquisitive men and each in his own mode had a professional interest in the matter in hand.

“Well,” he said, when they were settled, “how do you feel about Operation Esmeralda?”

They agreed, it appeared, that nothing had happened to contradict Alleyn’s theory. The reaction to the doll had been pretty well what he had predicted.

“Though the trouble is,” Father Jourdain added, “that when one is looking for peculiar behaviour one seems to see it all over the place. I must confess that I found Dale’s outburst, the Cuddys’ really almost gloating relish, Merryman’s intolerable pedantry, and McAngus’s manipulations equally disturbing. Of course it doesn’t arise,” he added after a pause, “but even poor Miss Abbott behaved, or so it seemed to me, with a kind of extravagance. I suppose I lost my eye.”

“Why,” Alleyn asked, “do you call her ‘poor Miss Abbott’?”

“Oh, my dear Alleyn! I think you know very well. The problem of the unhappy spinster crops up all along the line in my job.”

Tim gave an inarticulate grunt.

“Yes,” Alleyn said, “she is obviously unhappy.” He looked at Tim. “What did that knowledgeable noise mean?”

Tim said impatiently, “We’re not concerned with Miss Abbott, I imagine, but it meant that I too recognize the type, though perhaps my diagnosis would not appeal to Father Jourdain.”

“Would it not?” Father Jourdain said. “I should like to hear it all the same.”

Tim said rapidly, “No, really. I mustn’t bore you and at any rate one has no business to go by superficial impressions. It’s just that on the face of it she’s a textbook example of the woman without sexual attraction who hasn’t succeeded in finding a satisfactory adjustment.”

Alleyn looked up from his clasped hands. “From your point of view isn’t that also true of the sort of homicide we’re concerned with?”

“Invariably, I should say. These cases almost always point back to some childish tragedy in which the old gang — fear, frustration and jealousy — have been predominant. This is true of most psychological abnormalities. For instance, as a psychotherapist I would, if I got the chance, try to discover why hyacinths make Mr. Cuddy feel ill and I’d expect to find the answer in some incident that may have been thrust completely into his subconscious and that superficially may seem to have no direct reference to hyacinths. And with Aubyn Dale, I’d be interested to hunt down the basic reason for his love of practical jokes. While if Mr. Merryman were my patient, I’d try and find a reason for his chronic irritability.”

“Dyspepsia no good?” Alleyn asked. “He’s forever taking sodamints.”

“All dyspeptics are not irritable woman-haters. I’d expect to find that his indigestion is associated with some very long-standing psychic disturbance.”

“Such as his nurse having snatched away his favourite rattle and given it to his papa?”

“You might not be as far out as you may think you are, at that.”

“What about Dale and McAngus?”

“Oh,” Tim said, “I wouldn’t be surprised if Dale hadn’t achieved, on the whole, a fairly successful sublimation with his ghastly telly-therapy. He’s an exhibitionist who thinks he’s made good. That’s why his two public blunders upset his applecart and gave him his ‘nervous breakdown.’ ”

“I didn’t know he’d had one,” said Father Jourdain.

“He says he has. It’s a term psychotherapists don’t accept. As for McAngus, he really is interesting; all that timidity and absent-mindedness and losing his way in his own stories — very characteristic.”

“Of what?” Alleyn asked.

“Of an all-too-familiar type. Completely inhibited. Riddled with anxieties and frustrations. And of course he’s quite unconscious of their origins. His giving Mrs. D-B that damn doll was very suggestive. He’s a bachelor.”

“Oh, dear!” Father Jourdain murmured and at once added, “Pay no attention to me. Do go on.”

“Then,” Alleyn said, “the psychiatrist’s position in respect of these crimes is that they have all developed out of some profound emotional disturbance that the criminal is quite unaware of and is unable to control?”

“That’s it.”

“And does it follow that he may, at the conscious level, loathe what he does, try desperately hard to fight down the compulsion, and be filled with horror each time he fails?”

“Very likely.”

“Indeed, yes,” Father Jourdain said with great emphasis. “Indeed, indeed!”

Alleyn turned to him. “Then you agree with Makepiece?”

Father Jourdain passed a white hand over his dark luxuriant hair. “I’m sure,” he said, “that Makepiece has described the secondary cause and its subsequent results very learnedly and accurately.”

“The secondary cause!” Tim exclaimed.

“Yes. The repressed fear, or frustration or whatever it was — I’m afraid,” said Father Jourdain with a faint smile, “I haven’t mastered the terminology. But I’m sure you’re right about all that; indeed you know it all as a man of science. But you see I would look upon that early tragedy and its subsequent manifestations as the — well, as the modus operandi of an infinitely more terrible agent.”

“I don’t follow,” Tim said. “A more terrible agent?”

“Yes. The devil.”

“I beg your pardon?”

“I believe that this poor soul is possessed of a devil.”

Tim, to Alleyn’s amusement, actually blushed scarlet as if Father Jourdain had committed some frightful social solecism.

“I see,” Father Jourdain observed, “that I have embarrassed you.”

Tim mumbled something about everybody being entitled to his opinion.

Alleyn said, “I’m afraid I’m rather stuck for a remark, too. Forgive me, but you do mean, quite literally, exactly what you’ve just said? Yes, I’see you do.”

“Quite literally. It is a case of possession. I’ve seen too many to be mistaken.”

There was a long pause during which, Alleyn reminded himself that there were a great number of not unintelligent people in the world who managed, with some satisfaction to themselves, to believe in devils. At last he said, “I must say, in that case, I very much wish you could exorcise it.”

With perfect seriousness Father Jourdain replied that there were certain difficulties. “I shall, of course, continue to pray for him,” he said.

Tim shuffled his feet, lit a cigarette, and with an air of striking out rather wildly for some kind of raft, asked Alleyn for the police view of this kind of murder. “After all,” he said, “you must be said to be experts.”

“Not at all,” Alleyn rejoined. “Very far from it. Our job, God save the mark, is first to protect society and then as a corollary to catch the criminal. These sorts of criminals are often our worst headache. They have no occupational habits. They resemble each other only in their desire to kill for gratification. In everyday life they may be anything; there are no outward signs. We generally get them but by no means always. The thing one looks for, of course, is a departure from routine. If there’s no known routine, if your man is a solitary creature as Jack the Ripper was, your chances lessen considerably.” Alleyn paused and then added in a changed voice: “But as to why, fundamentally, he is what he is — we are dumb. Perhaps if we knew we’d find our job intolerable.”