"After your grandfather's death he was in possession of the house for a time, and the keys would be with him. In handing them to Lord Derrington's agent he might have forgotten one." "It's improbable!" "I don't think so. It was a chance, I think, at first, but when he knew that Mrs. Jersey occupied the house he might have found the latch-key useful to see her when he felt inclined. I dare say she tried to get money out of him again." "But he refused her." "He did--once," said Bawdsey, meaningly, "but Mr. Ireland was not so young as he had been, and dreaded lest his--accident should be known." "It was an accident," said George. "Much as I deplore the death of my father, yet I acquit Ireland of all blame. But he didn't know she lived here until Miss Bull told him." "Oh, yes, he did. I'm sure Mrs. Jersey would let him know that she was just round the corner. She always kept in touch with useful friends." "But why should he kill her so suddenly?" "Well, he might have heard that she had written out a confession, or even about Lord Derrington's visit. And then he would come round to ask her if she had incriminated him in her confession. He would ask her for a sight of it. Not having it, for she found the blue envelope empty after Lola left, she would deny that she had it. The stiletto left by Lola would be on the table. What was more natural than for Ireland to pick it up and kill her in a sudden access of dread? Remember, Mrs. Jersey could accuse him of the crime, as it was known that Ireland was jealous of your mother's marriage to Vane. Oh, there was plenty of motive. As to his having refused her before, he was getting old, and thinking he might be brought to justice by her confession, for he never knew when she would die or into whose hands it would fall, he might have lost his nerve." "It strikes me that if he struck the blow he had a great deal of nerve," said George, dryly; "but you go on a lot of suppositions. You suppose that Ireland retained a latch-key of this house, that he knew Mrs. Jersey had written out a confession, that he knew my grandfather was coming on that night--in fact, that's all theory, Bawdsey. I do not believe Mr. Ireland had anything to do with the matter." "Then who had?" asked the detective. "What would you say to Margery?" "What, the niece--that half-witted girl?" "Exactly. Half-witted. She is more like an animal than anything human. She gets these sudden fits of rage. When Miss Bull fainted Margery rushed in and threatened me with her fists. Seeing what an uncontrollable temper she had, it occurred to me that she might have killed her aunt." "But Miss Bull says that the aunt locked the girl in her room." "Of course, but Miss Bull may know the truth, and may be shielding Margery--she seems to have a strange affection for the girl. What if Mrs. Jersey--to vary the story--found Margery down the stairs after Lola was gone, and instead of rebuking her as Miss Bull said in the passage----"