"Well, I suppose you couldn't foresee that we should want him. I don't expect he'll turn up in this neighbourhood again." "What's your theory, sir?" "It's early to form one, Mulligan. I fancy two men killed this woman. The one you saw kept you in conversation, while the other murdered the woman, and then cleared, while his accomplice led you away. Did you hear a scream?" "No, sir. The song ended as we left the gate, and in a few minutes we were too far away to hear any cry." "As I thought. The man was an accomplice sent out to lure you away." "It might be, sir," confessed Mulligan. "I was leaning over the gate when the young gentleman came out." "The men saw you from the window, and as they couldn't kill the woman while you were there, Number One went out to draw you away, while Number Two remained behind to commit the crime. At what hour did you part with Number One?" "Half-past eleven, sir. I was with him thirty minutes." "Time enough for Number Two to murder the woman and make off. He escaped by the front door, since you say the back premises are locked up. Ah! there's the doctor. Go to the station and send on----" Here Derrick named two of his most trusted subordinates. When Mulligan left, the inspector resumed his examination. Already he had looked over the clothing of the deceased. She was plainly but tastefully dressed in black, but wore no ornaments. Everything was of good quality, but made without trimmings. The under-linen was equally fine, but on it the inspector could find no mark or initials likely to indicate the name. Apparently she had been seated at the piano when stabbed, and had fallen dead on the bearskin almost without a cry. The assassin had assured himself that she was dead, then had turned her face downward, so as to avoid the horrified stare of those wide-open eyes. At least this was the inspector's view. "A pretty woman," said Derrick musingly. "Fair, slender, blue eyes, delicate hands. I should think she was a lady. Married"--he touched the ring--"but not rich, since she wears no ornaments. Careful in her dress, but, not mean, and not fashionable either. Hullo!" This exclamation was drawn from him by the sight of a hat and cloak thrown over a chair on the further side of the piano. These were also fine, but neat and unpretentious. The woman must have come to the house on a visit, since she certainly would not have placed her out-of-door things in such a place and have sat down had she a bedroom in the house. But what was she doing in a mansion, the owner of which was at the seaside? Had the first man let her in with his latch-key, and if so, how did he come to be in possession of the latch-key? These were questions which the inspector was trying to answer when the doctor arrived.