"If you will all be so kind as to step into the library in an hour's time," he said blandly, "I should like to reconstruct the scene of last night's tragedy in the presence of all those who took part in it.... No, Miss Duggan, you need not be afraid. Your father's body will have been removed by then. But if any one of you have any knowledge whatever to impart to me--representing, as I do, Scotland Yard in the absence of Mr. Narkom (who is already upon his way here), I shall be only too pleased to speak with you in the little ante-room close by. I may use that as a sort of office, for the time being, may I not, Lady Paula? You've no objections, I trust?" She shook her head at him, flashing him a killing glance from under her full lids. The flattery of his choice of her as principal of the bereft family pleased her immensely. "None whatever." "Thanks very much." Then he withdrew to the said ante-room, took out pen and paper, and began figuring out something upon it which caused him not a little worry, by the look of his face. Five minutes brought a gentle tap upon the door, and without raising his head from his work he called, "Come in." Catherine Dowd stood in the aperture, looking more like the Mona Lisa than he had ever seen a living person do before. There was something of the same inscrutable smile lingering upon her lips, the same mysterious impassivity in her quiet countenance. "I've brought you something, Mr. Deland," she said in a soft purring voice. "Something which I imagine has great bearings upon last night's tragedy and which I found hidden in the left-hand curtain of the window. It was stuck carelessly into the inner lining of the green silk, and hung there. Here it is." Cleek was on his feet in an instant, face alert. She handed him the object, and then nodded at his exclamation of surprise. "Yes. A stiletto. And in the face of the fact that Sir Andrew was stabbed as well as shot, something of importance." "I should think so, indeed!" Cleek's face fairly radiated excitement as he bent over the object that lay in his open palm, touching it with light, nimble fingers. "Gad! yes! A stiletto--and a South American one at that! See the curiously square blade? If that isn't the identical instrument that stabbed Sir Andrew's breast, I'll eat my hat! Miss Dowd, you have brought me a clue which may lead to the tracing of the murderer himself--or one of 'em, as there must have been two. Now, tell exactly the circumstances in which you found it, and why you kept the fact hidden until now?" She came a little nearer to him and leaned against the edge of the desk-top, a sort of secretive nonchalance in her attitude.