‘Because I think you may help me to clear him. Please consider the facts. The medical evidence shows Sir William was murdered some time after 8.30 on the evening of Wednesday week. We know that Mr Cosgrove Ponson was financially in low water—in fact, was in debt for a very large sum, and under threat of exposure and ruin unless he paid up. We know also he benefited to a considerable extent under Sir William’s will. Further, in the boathouse from which Sir William’s body was set adrift, a cigarette end was found—one of a peculiar brand, but little smoked in England, but which Mr Ponson continually uses, and lastly, and this is what brings me to you today, Mr Ponson has been unable to account satisfactorily for his time on the evening in question. He says he was with you from 8.30 till 9.00, and what I want to ask you is, Can we get proof of that? I think you will appreciate that proof of that means proof of his innocence.’ Tanner had been unobtrusively watching his companion while he spoke, and her demeanour interested him keenly. While he was recounting the medical evidence and Cosgrove’s financial position she had listened perfunctorily, as if bored by such trifles being brought to her notice. But when he mentioned the cigarette she started and a look first of fear and then of anger showed momentarily in her eyes. It seemed to Tanner she might have so acted if she knew Cosgrove was guilty—as if she was aware of and prepared for all he had to say except this about the cigarette, and that her anger was against Cosgrove for having smoked under such circumstances. She did not speak for some moments, and Tanner felt instinctively she had seen his little trap, and was considering a way out. At last she appeared to come to a conclusion, and replied in a quiet voice: ‘What Mr Ponson has told you is quite true, or at least almost. He was at my room at the Follies for about half an hour that evening, but not quite at the hour you have mentioned. He came about half-past nine, and left at ten. I know the time because it is the only period in that play during which I am off the stage.’ She had avoided his trap anyway, and her answer confirmed Cosgrove’s story. But Tanner recognised he was dealing with a very clever woman, and he was by no means so convinced of the truth of her statement as he was of that of the butler. He went on: ‘Obviously, madame, if we have to go before a jury the more corroborative evidence we can get the better. Now, are there any other persons who might have seen Mr Ponson at the theatre, and who could be called to add their testimonies?’ ‘I don’t know if anyone else actually saw Mr Ponson,’ she answered, ‘but I should think it likely. Probably the door-keeper did, or one of the other men. Have you made inquiries?’ ‘No, madame. Not yet.’ ‘Well, you had better do so,’ and she got up to indicate that the interview was at an end.