They continued discussing the affair for some time. Jimmy could see that in spite of the brave face Lois put on things, she was deeply worried and despondent. Never had he admired her more. He marvelled at her belief in Austin, her assurance that he, Jimmy, was doing the utmost possible, her fairness to Tanner, and her utter and absolute forgetfulness of herself. As he saw her to the train he felt his resolution strengthened, to spare himself neither time nor money to bring about the result she desired. When Tanner left Daunt’s office on the previous day, he returned at once to the Yard. First he arranged for Cosgrove to be shadowed, in case that gentleman, learning of Douglas’s arrest, might consider discretion the better part of valour and disappear. Then he busied himself in re-examining the witnesses of Cosgrove’s movements on the night of the murder, which the efforts of Lois and Daunt had unearthed. When he had heard their statements he had to admit himself convinced of the cousin’s duplicity. After a consultation with his chief a warrant was issued, and Tanner went to the flat in Knightsbridge and executed it. When cautioned, Cosgrove made no statement beyond earnestly and emphatically protesting his innocence, and declaring that a terrible mistake had been made. A detailed search of the flat revealed one or two things which Tanner had not already known. As he had suspected on the occasion of his first visit, Cosgrove had a second desk for his more private papers. In the dressing-room was an old Sheraton escritoire, and there the Inspector found complete information about his prisoner’s finances. The latter appeared even more involved than Tanner had suspected, which of course strengthened the motive for the murder, and therefore the case against the accused. But this was not all. The motive had been stronger than any merely financial embarrassment could have made it. In the same desk was a bundle of letters from the actress at the Follies, Miss Betty Belcher. These showed that Cosgrove’s relations with her had been extremely intimate. For a considerable time he had evidently been pressing her to marry him, and in one letter, dated about three weeks before Sir William’s death, she had openly admitted she loved him and would marry him if only he were rich. ‘You know, Cos.,’ the rather cynical letter went on, ‘it would be absurd for me to think of marrying a poor man. I have been too long accustomed to all that money gives to contemplate any other kind of life. If you had a fortune—well, I might consider it, but as things are you must see it would be out of the question.’ ‘He must have been far gone to want to marry her after that,’ mused Tanner, ‘but he evidently did, for here a week later is another letter in the same strain.’ He filed the papers in the Cosgrove dossier, from which they duly found their way into the hands of the public prosecutor.