‘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?’