Stone had examined the sitting room where Mrs. Pell had died, and, closing its door, had returned to the big living room, for further information on the whole subject of the crime and its subsequent events. "The pin's the thing," he said, at last. "Everything hinges on that." "Do you think so?" asked Mr. Chapin. "It seems to me the pin's a blind--a decoy--and the people hunting it are really after something else, of intrinsic value." Fleming Stone looked at the lawyer, with a courteous impatience. "No, Mr. Chapin, the pin is the thing they are after. It was for that pin that Mrs. Pell was murdered. That is why her dress was torn open at the throat, the villain was searching for that pin. That's why the desk was ransacked, the handbag explored, the pocket-book emptied--all in a desperate effort to find that seemingly insignificant pin! That is why the poor woman was tortured, maltreated, bruised and beaten, in final attempts to make her tell where the pin was. Failing, the wretch flung her to the floor, in a burst of murderous frenzy." "That's why I was kidnapped, then," exclaimed Iris. "Of course, and you may be again! Those people will stop at nothing! The letters asking for the pin, the caller who wanted it for his 'collection,' all represent the same master-mind, who is after the pin. "But why?" wondered Hughes, "what do they want of the pin?" "The pin means the jewels," declared Stone, briefly. "How, I can't say, exactly, for the moment, but the pin is the open sesame to the hiding-place of the gems, and only the possession of it will secure the treasure. We must get the pin--and then, all else will be clear sailing." "But the pin is gone," lamented Iris. "That is the worst phase of it all," Stone said, regretfully. "It is such a difficult thing to trace--not only so tiny, and easily lost, but so like thousands of others, that it can't readily be discerned even if seen." "You think it's just an ordinary pin, then?" inquired Chapin. "Absolutely, sir." "Then why won't any other pin do as well?" Stone looked at him keenly. "I can't answer that at present, Mr. Chapin; my theory regarding the pin, while doubtless the truth, is as yet uncertain. Now, another and equally great problem is that of the murderer's exit. From your story of the crime, I gather that the room was absolutely unenterable, except by breaking in the door, which Purdy and the chauffeur did?" "That is true," agreed Iris; "the windows, as you can see, are strongly barred, and there is but the one door. Search has been made for secret entrances or concealed passages, but there is nothing of the sort." "No," said Stone, "this sort of a house is not apt to have such. If there were any, they would be easily discovered. And there were several people in this room, when the two men burst in the door?" "Yes," said Iris. "I was here, and Polly, the cook, and the two men----"