True, there were circumstances which might serve to incriminate Robert Fenley; but if that young man were really responsible for the crime, he was what "the Yard" classes privately as a monumental idiot, since his subsequent conduct was well calculated to arouse the suspicion which the instinct of self-preservation would try to avert. A long experience of the methods of criminals warned Winter of the folly of jumping at conclusions, but he would be slow to admit and hard to be convinced that Robert Fenley took any active part in his father's murder. Of course, it was not with a view toward indulging in a reverie that he approached the window. He was setting a simple trap, into which many a man and woman had fallen. Any one of moderately strong character can control face and eyes when the need of such discipline is urgent, but howsoever impregnable the mask, the strain of wearing it is felt, and relief shows itself in an unguarded moment. At the farther end of the room there was a mirror above the fireplace, and as he turned his back on Fenley, by a hardly perceptible inclination of his head he could catch the reflection of his companion's face. The maneuver succeeded, but its result was negative. Hilton Fenley's eyes were downcast. He had lifted a hand to his chin in one of those nervous gestures which had been so noticeable during the morning's tumult. His face wore an expression of deep thought. Indeed, he might be weighing each word he had heard and uttered, and calculating its effect on his own fortunes. Still obeying that unworthy instinct which bade him sting Fenley into defiance, Winter tossed a question over his shoulder. "May I have a word with Miss Garth?" he said suddenly. "Why?" was the calm answer. "Just to settle that telephone incident once and for all." "But if you imagine it might not have been Miss Garth who made the call, why are you here?" Then the detective laughed. His wonted air of cheerful good humor smoothed the wrinkles from his forehead. He was beaten, completely discomfited, and he might as well confess it and betake himself to some quarter where a likelier trail could be followed. "True," he said affably. "I need not bother the young lady. Perhaps you will make my excuses and tell her that I ran you to earth in Gloucester Mansions merely to save time. By the way, I led the youth at the call office to believe that I was searching for an undersized Polish Jewess, all nose and gold earrings, a description which hardly applies to Miss Garth. And one last question--do you return to Roxton tonight?" "Within the hour."