“Why did she kill him?”

“Because he’d lost his nerve. This morning we questioned him about the lift and about his legacy. He went to pieces. He was a stupid fellow, ready enough to act quickly when the brains of the party shoved the weapon in his hand and egged him on, but wildly incapable of keeping his head afterwards, when the mental rot set in. No doubt he returned to Brummell Street in a state of terror and Tinkerton decided he was dangerous. She’s a clever, a desperate and a courageous woman. Moreover she is in her mistress’ confidence. I’ll bet you anything you like that Tinkerton is the buyer of whatever drug Lady Wutherwood takes and that she gets a little commission on the side. As Lady Wutherwood’s confidante, she undoubtedly knows a great deal about the witchcraft business. We shall only find Lady Wutherwood’s prints on the—” Alleyn checked himself—“on the objects connected with this last crime, but I’ll stake my life that Tinkerton visited the kitchen sometime during the night and brought away an instrument which she laid ready to hand in the green drawing-room. You may be sure Tinkerton knew very well what her mistress meant to do during the small hours. You may be sure it was Tinkerton who suggested that Lady Wutherwood should test the power of the Hand of Glory and Tinkerton who slipped down the backstairs and pulled out the fuse plug. One can imagine the instructions that were poured into that demented ear. First she was to secure the hand, then take it up to the top landing and down the deserted passage to the end room. There she would find a sleeping man. Let her make any noise she could think of, drop his heavy boots on the floor, scream, shake the bed. No one would stir, said Tinkerton, for all would be under the soporific spell of the severed hand.”

“So poor Aunt V. was the cat’s-paw.”

“Yes. Tinkerton may even have persuaded her that her Little Master required the death of the chauffeur. She may have told her where to find the razor. Her prints on the razor would be useful and her reaction when she found Giggle already murdered wouldn’t matter. Let her make whatever noise she liked. Let her be found there, with the razor in her hand. I’m sorry, Miss Grey, it’s a beastly story but I think you’ll feel better if you know exactly what happened, however unpleasant the recital.”

“Yes,” said Roberta. “But I still don’t quite see.”

“It may be Aunt V., after all,” said Henry. “Egged on by Tinkerton.”

“No. Only a left-handed person could have done it. I shan’t describe the nature of the injury.”

“I’d rather you did,” said Henry. “Robin, dear, perhaps if you—”

“I’d rather know, too, Henry. It’s beastly to wonder.”

“Well,” said Alleyn, “the murderer stood behind the head of the bed and the angle and position of the injury precludes any possibility of it being a right-handed attack. That’s all you need to know, isn’t it?”