‘You knew! All these years you have watched me, and known how much I suffered. Why did you hide the letter? Why did you marry me, knowing my past history? It seems to me you must be mad. I understand now why you have watched me, why, since this awful business, you have never taken your eyes off me. You knew. You knew I was being blackmailed.’ She caught her breath, and moved round stiffly until she faced her husband. ‘You’ve done it,’ she whispered. ‘It’s you. You’re mad, and you’ve done it to torture me. You’ve always been jealous of Paddy. Ever since I told you it could never be the same with anyone else. You were jealous of dead Paddy.’

‘Evelyn,’ said Alleyn gently. She made a slight impatient gesture, but she spoke only to Carrados.

‘You wrote those letters. It’s you.’

Carrados stared at her like an idiot. His mouth was open. His eyebrows were raised in a sort of imbecile astonishment. He shook his head from side to side.

‘No,’ he said. ‘No, Evelyn, no.’

‘Make him tell you, Roderick,’ she said, without turning her head.

‘Sir Herbert,’ said Alleyn. ‘Do you deny you kept this letter in the secret drawer of that desk?’

‘Yes.’

Fox glanced at Alleyn, went out, and returned, after another deadly silence, with Bridget.

Lady Carrados gave a little moaning cry, and caught at her daughter’s hand.

‘Miss O’Brien,’ said Alleyn, ‘I’ve asked you to come here in order that the Assistant Commissioner may hear of an incident you related to me yesterday. You told me that on one occasion, when you were alone in the study of your stepfather’s house, you examined the miniature writing-cabinet in that room. You told me that when you pressed a tiny screw a triangular drawer opened out of the cabinet, and that there was a letter in it. Is this true?’

‘Donna?’ Bridget looked anxiously at her mother.

‘Yes, yes, darling. Tell them. Whatever it is, tell them.’

‘It’s quite true,’ said Bridget.

‘Your stepfather came into the study at this juncture?’

‘Yes.’

‘What was his attitude when he saw what you had done?’

‘He was very angry indeed.’

‘What did he do?’

‘He twisted my arm, and bruised it.’

‘A lie. The child has always hated me. Everything I have tried to do for her—a lie, a wicked spiteful lie!’

‘Fox,’ said Alleyn, ‘will you ask Sir Daniel to come in?’

Sir Daniel had evidently been sitting in the secretary’s office, as he came in almost immediately. When he saw the two Carradoses and Bridget, he greeted them exactly as if they were fellow guests at a party. He then shook hands with the Assistant Commissioner, and turned to Alleyn.

‘Sir Daniel,’ said Alleyn. ‘I’ve asked you to come in as I understand you were witness to a scene which Miss O’Brien has just described to us. It took place about two years ago. Do you remember that Miss O’Brien rang you up and asked you to come and see her mother who was unwell?’