She shot a horrified glance at Fox, and Alleyn answered it.

“Mr Fox is fully acquainted with the whole story,” he said. “He agrees with me that your friend had better dissolve. We realize that beyond all doubt you yourself were the victim of these blackmailing letters. There is no need for you to feel particularly distressed over this. It is much better to tackle this sort of thing without the aid of an imaginary Mrs X. She makes for unnecessary confusion. We now have the facts—”

“But — how do you —?”

Alleyn decided to take a risk. It was a grave risk.

“I have already spoken to Captain Withers,” he said.

“My God, has Maurice confessed?”

Fox’s notebook dropped to the floor.

Alleyn, still watching the gaping mouth with its wet red margin, said: “Captain Withers has confessed nothing.” And he thought: “Does she realize the damage she’s done?”

“But I don’t mean that,” Mrs Halcut-Hackett gabbled. “I don’t mean that. It’s not that. You must be crazy. He couldn’t have done it.” She clenched her hands and drummed with her fists on the arms of the chair. “What did he tell you?”

“Very little I’m afraid. Still we learned at least that it was not impossible—”

“You must be crazy to think he did it. I tell you he couldn’t do it.”

“He couldn’t do what, Mrs Halcut-Hackett?” asked Alleyn.

“The thing — Lord Robert…” She gaped horridly and then with a quick and vulgar gesture, covered her mouth with her ringed hand. Horrified intelligence looked out of her eyes.

“What did you think Captain Withers had confessed?”

“Nothing to do with this. Nothing that matters to anyone but me. I didn’t mean a thing by it. You’ve trapped me. It’s not fair.”

“For your own sake,” said Alleyn, “you would be wise to try to answer me. You say you did not mean to ask if Captain Withers had confessed to murder. Very well, I accept that for the moment. What might he have confessed? That he was the author of the letter your blackmailer had threatened to use. Is that it?”

“I won’t answer. I won’t say anything more. You’re trying to trap me.”

“What conclusion am I likely to draw from your refusal to answer? Believe me, you take a very grave risk if you refuse.”

“Have you told my husband about the letter?”

“No. Nor shall I do so if it can be avoided. Come now.” Alleyn deliberately drew all his power of concentration to a fine point. He saw his dominance drill like a sort of mental gimlet through her flabby resistance. “Come now. Captain Withers is the author of this letter. Isn’t he?”

“Yes, but—”

“Did you think he had confessed as much?”

“Why, yes, but—”

“And you suppose Lord Robert Gospell to have been the blackmailer? Ever since that afternoon when he sat behind you at the concert?”

“Then it was Robert Gospell!” Her head jerked back. She looked venomously triumphant.

“No,” said Alleyn. “That was a mistake. Lord Robert was not a blackmailer.”

“He was. I know he was. Do you think I didn’t see him last night, watching us. Why did he ask me about Maurice? Why did Maurice warn me against him?”

“Did Captain Withers suggest that Lord Robert was a blackmailer?” In spite of himself a kind of cold disgust deadened Alleyn’s voice. She must have heard it because she cried out:

“Why do you speak of him like that? Of Captain Withers, I mean. You’ve no right to insult him.”

“My God, this is a stupid woman,” thought Alleyn. Aloud he said: “Have I insulted him? If so I have gone very far beyond my duty. Mrs Halcut-Hackett, when did you first miss this letter?”

“About six months ago. After my charade party in the little season.”

“Where did you keep it?”

“In a trinket-box on my dressing-table.”

“A locked box?”

“Yes. But the key was sometimes left with others in the drawer of the dressing-table.”

“Did you suspect your maid?”

“No. I can’t suspect her. She has been with me for fifteen years. She’s my old dresser. I know she wouldn’t do it.”

“Have you any idea who could have taken it?”

“I can’t think, except that for my charade party I turned my room into a buffet, and the men moved everything round.”

“What men?”

“The caterer’s men. Dimitri. But Dimitri superintended them the whole time. I don’t believe they had an opportunity.”

“I see,” said Alleyn.

He saw she now watched him with a different kind of awareness. Alleyn had interviewed a great number of Mrs Halcut-Hacketts in his day. He knew very well that with such women he carried a weapon that he was loath to use, but which nevertheless fought for him. This was the weapon of his sex. He saw with violent distaste that some taint of pleasure threaded her fear of him. And the inexorable logic of thought presented him to himself, side by side with her lover.

He said: “Suppose we get the position clear. In your own interest I may tell you that we have already gathered a great deal of information. Lord Robert was helping us on the blackmail case, and he has left us his notes. From them and from our subsequent enquiries we have pieced this much together. In your own case Captain Withers was the subject of the blackmailing letters. Following our advice you carried out the blackmailer’s instruction and left your bag in the corner of the sofa at the Constance Street Hall. It was taken. Because Lord Robert deliberately sat next to you and because Captain Withers had, as you put it, warned you against him, you came to the conclusion that Lord Robert took the bag and was therefore your blackmailer. Why did you not report to the police the circumstances of the affair at the concert? You had agreed to do so. Were you advised to let the case drop as far as the Yard was concerned?”

“Yes.”

“By Captain Withers? I see. That brings us to last night. You say you noticed that Lord Robert watched you both during the ball. I must ask you again if Captain Withers agrees with your theory that Lord Robert was a blackmailer.”

“He — he simply warned me against Lord Robert.”

“In view of these letters and the sums of money the blackmailer demanded, did you think it advisable to keep up your friendship with Captain Withers?”

“We — there was nothing anybody could — I mean—”

“What do you mean?” asked Alleyn sternly.

She wetted her lips. Again he saw that look of subservience and thought that of all traits in an ageing woman this was the unloveliest and most pitiable.

She said: “Our friendship is partly a business relationship.”

“A business relationship?” Alleyn repeated the words blankly.

“Yes. You see Maurice — Captain Withers — has very kindly offered to advise me and — I mean right now Captain Withers has in mind a little business venture in which I am interested, and I naturally require to talk things over so — you see —?”

“Yes,” said Alleyn gently, “I do see. This venture of Captain Withers is of course the club at Leatherhead, isn’t it?”

“Why, yes, but—”

“Now then,” said Alleyn quickly, “about last night. Lord Robert offered to see you home, didn’t he? You refused or avoided giving an answer. Did you go home alone?”

She might as well have asked him how much he knew, so clearly did he read the question in her eyes. He thanked his stars that he had made such a fuss over Withers’s telephone. Evidently Withers had not rung her up to warn her what to say. Frightened his call would be tapped, thought Alleyn with satisfaction, and decided to risk a further assumption. He said:

“You saw Captain Withers again after the ball, didn’t you?”

“What makes you think that?”

“I have every reason to believe it. Captain Withers’s car was parked in a side street off Belgrave Square. How long did you sit there waiting for him?”

“I don’t admit I sat there.”

“Then if Captain Withers tells me he took a partner to the Matador last night after the ball I am to conclude that it was not you?”