Alleyn said: “Most of what I have to say is addressed to you, Sir Herbert.”

“Indeed?” said Carrados. “Well, Alleyn, as I fancy I told you yesterday afternoon, I am only too anxious to help you to clear up the wretched business. As Lord Robert’s host on that fatal night—”

“Yes, we quite realize that, sir. Your attitude encourages one to hope that you will understand, or at any rate excuse, my going over old ground, and also breaking into new. I am in a position to tell you that we have followed a very strange trail since yesterday — a trail that has led us to some remarkable conclusions.”

Carrados turned his eyes, but not his head, towards his wife. He did not speak.

“We have reason to believe,” Alleyn went on, “that the murder of Lord Robert Gospell is the outcome of blackmail. Did you speak, sir?”

“No. No! I cannot see, I fail to understand—”

“I’ll make myself clearer in a moment, I hope. Now, for reasons into which I need not go at the moment, the connection between this crime and blackmail leads us to one of two conclusions. Either Lord Robert was a blackmailer, and was killed by one of his victims, or possibly someone wishing to protect his victim—”

“What makes you say that?” asked Carrados hoarsely. “It’s impossible!”

“Impossible? Why, please?”

“Because, Lord Robert, Lord Robert was not — it’s impossible to imagine — have you any proof that he was a blackmailer?”

“The alternative is that Lord Robert had discovered the identity of the blackmailer, and was murdered before he could reveal it.”

“You say this,” said Carrados, breathlessly, “but you give no proof.”

“I ask you, sir, simply to accept my statement that rightly or wrongly we believe our case to rest on one or the other of those alternatives.”

“I don’t pretend to be a detective, Alleyn, but—”

“Just a minute, sir, if you don’t mind. I want you now to go back with me to a day nearly eighteen years ago, when you motored Lady Carrados down to a village called Falconbridge in Buckinghamshire. You were not married then.”

“I frequently motored her into the country in those days.”

“You will have no difficulty in remembering this occasion. It was the day on which Captain Paddy O’Brien met with his accident.”

Alleyn waited. He saw the sweat round Carrados’s eyes shine in the strong lamplight.

“Well?” said Carrados.

“You do remember that day?” Alleyn asked.

“But Herbert,” said Lady Carrados, “of course you do.”

“I remember, yes. But I fail to see—”

“Please, sir! I shall fire point-blank in a moment. You remember?”

“Naturally.”

“You remember that Captain O’Brien was taken first to the vicarage and from there, in an ambulance, to the hospital, where he died a few hours later?”

“Yes.”

“You remember that, after he died, your wife, as she is now, was very distressed because she believed that a certain letter which Captain O’Brien carried had been lost?”

“I have no recollection of this.”

“Let me help you. She said that he had probably carried it in his pocket, that it must have fallen out, that she was most anxious to recover it. Am I right, Lady Carrados?”

“Yes — quite right.”

Her voice was low, but perfectly steady. She was looking at Alleyn with an air of shocked bewilderment.

“Did you ask Sir Herbert if he had enquired everywhere for this missing letter?”

“Yes.”

“Do you remember now, Sir Herbert?”

“I think — I remember — something. It was all very distressing. I tried to be of some use; I think I may have been of some use.”

“Did you succeed in finding the letter?”

“I — don’t think so.”

“Are you sure?”

A little runnel of sweat trickled down each side of his nose into that fine moustache.

“I am tolerably certain.”

“Do you remember sitting in your car outside the hospital while Lady Carrados was with Captain O’Brien?”

Carrados did not speak for a long time. Then he swung round in his chair, and addressed that silent figure in the green lamplight.

“I can see no possible reason for this extraordinary procedure. It is most distressing for my wife, and I may say, sir, it strikes me as being damnably offensive and outside the duties of your office.”

“I don’t think it is, Sir Herbert,” said the Assistant Commissioner. “I advise you to answer Mr Alleyn, you know.”

“I may tell you,” Carrados began, “that I am an intimate friend of your chiefs. He shall hear about this.”

“I expect so,” said the Assistant Commissioner. “Go on, Mr Alleyn.”

“Lady Carrados,” said Alleyn, “did you, in point of fact, leave Sir Herbert in the car when you went into the hospital?”

“Yes.”

“Yes. Now, Sir Herbert, while you waited there, do you remember a schoolgirl of fifteen or so coming up on her bicycle?”

“How the devil can I remember a schoolgirl on a bicycle eighteen years ago?”

“Only because she gave you the letter that we have been discussing.”

Evelyn Carrados uttered a stifled cry. She turned and looked at her husband, as though she saw him for the first time. He met her with what Alleyn thought one of the most extraordinary glances he had ever seen — accusation, abasement, even a sort of triumphant misery, were all expressed in it; it was the face of a mean martyr. “The mask of jealousy,” thought Alleyn. “There’s nothing more pitiable or more degrading. My God, if ever I—” He thrust the thought from him, and began again.

“Sir Herbert, did you take that letter from the schoolgirl on the bicycle?”

Still with a sort of smile on his mouth, Carrados turned to Alleyn.

“I have no recollection of it,” he said.

Alleyn nodded to Fox, who went out. He was away for perhaps two minutes. Nobody spoke. Lady Carrados had bent her head, and seemed to look with profound attention at her gloved hands, clasped tightly together in her lap. Carrados suddenly wiped his face with his palm, and then drew out his handkerchief. Fox came back.

He ushered in Miss Harris.

“Good evening, Miss Harris,” said Alleyn.

“Good evening, Mr Alleyn. Good evening, Lady Carrados. Good evening, Sir Herbert. Good evening,” concluded Miss Harris with a collected glance at the Assistant Commissioner.

“Miss Harris,” said Alleyn, “do you remember staying with your uncle, Mr Walter Harris, when he was vicar at Falconbridge? You were fifteen at the time I mean.”

“Yes Mr Alleyn, certainly,” said Miss Harris.

Carrados uttered some sort of oath. Lady Carrados said: “ But — what do you mean, Miss Harris?”

“Certainly, Lady Carrados,” said Miss Harris brightly.

“At that time,” said Alleyn, “there was a fatal motor accident.”

“To Captain O’Brien. Pardon me, Lady Carrados. Yes, Mr Alleyn.”

“Good Lord!” ejaculated Alleyn, involuntarily. “Do you mean to say that you have realized that—”

“I knew Captain ‘Paddy’ O’Brien was Lady Carrados’s first husband, naturally.”

“But,” said Alleyn, “did you never think of telling Lady Carrados that there was this, well, this link, between you?”

“Oh, no,” said Miss Harris, “naturally not, Mr Alleyn. It would not have been at all my place to bring it up. When I was given the list of vacant posts at the Friendly Cousins Registry Office I thought this seemed the most suitable, and I — please excuse me, Lady Carrados — I made enquiries, as one does, you know. And I said to my friend Miss Smith: ‘What an extraordinary coincidence,’ because when I learned of Lady Carrados’s former name I realized it must be the same, and I said to Smithy: ‘I think that must be an omen,’ so I applied for the post.”

“I see,” said Alleyn, “and do you remember Sir Herbert, too?”

“Oh, yes. At least, I wasn’t quite sure at first, but afterwards I was. Sir Herbert was the gentleman in the car. Perhaps I should explain?”

“Please do.”

“I had actually spoken to him.” She looked apologetically at Carrados. “I’m quite sure Sir Herbert has quite forgotten, because I was just a gawky schoolgirl at the time.”