"Your confidence is quite safe with me, Tufnell," the detective added after a pause. "But I cannot answer your question at present."
"Very well, sir." The butler turned to the sideboard again without further remark, and left the dining-room a few minutes later.
Colwyn went to his room shortly afterwards, and occupied himself for a couple of hours in going through his notes of the case. It was his intention to defer his visit to the bedroom in the left wing until the household had retired, so as to be free from the curious speculations and tittle-tattle of the servants.
The moat-house kept country hours, and when he had finished his writing and descended from his room he found the ground floor in darkness. A clock somewhere in the stillness chimed solemnly as he walked swiftly across the hall. Its strokes finished proclaiming the hour of eleven as he mounted the staircase of the left wing.
The loneliness of the deserted wing was like a moving shuddering thing in the desolation of the silence and the darkness. It was as though the echoing corridor and the empty rooms were whispering, with the appeal of the forgotten, for friendly human companionship and light to disperse the horror of sinister shapes and brooding shadows which lurked in the abode of murder. Colwyn entered the bedroom where Mrs. Heredith had been murdered, and by the ray of his electric torch crossed to the bedside and switched on the light.
He stood there motionless for a while, trying to picture the manner and the method of the murder. If Hazel Rath had spoken the truth, the murderer had stood where he was now standing when the girl entered the room in the darkness. Had the light from the corridor, streaming through the open door, revealed her approaching figure to him? How long had he been there in the darkness, waiting for the moment to kill the woman on the bed?
If Nepcote was the murderer he must have entered almost immediately before, because he could not have reached the moat-house until nearly half-past seven, and the shot was fired at twenty minutes to eight. How had he known that Mrs. Heredith was there alone, in the darkness? A secret assignation might have been the explanation if the time had been after, instead of before the household's departure for the evening. But even the most wanton pair of lovers would hesitate to indulge their passion while the risk of chance discovery and exposure was so great.
As he pondered over the two stories Colwyn did not attempt to shut his eyes to the fact that Hazel, on her own showing, fitted into the crime more completely than Nepcote. She had ample opportunities to slip into the room and murder the woman who had supplanted her. She had really strengthened the case against herself by the damaging admission that she had sought Mrs. Heredith's room in secret just before the crime was committed. Her explanation of the scream and the shot was so improbable as to sound incredible. It was not to be wondered that Scotland Yard preferred to believe that it was the apparition of the frantic girl, revolver in hand, which had caused her affrighted victim to utter one wild scream before the shot was fired which ended her life.
But Colwyn had never allowed himself to be swayed too much by circumstance. Appearances were not always a safe guide in the complicated tangle of human affairs. Things were forever happening which left experience wide-eyed with astonishment. The contradictions of human nature persisted in all human acts. In this moat-house mystery, the grimmest paradox of his brilliant career, Colwyn was determined not to accept the presumption of the facts until he had satisfied himself that no other interpretation was possible. His subtle mind had been challenged by a finger-post of doubt in the written evidence; a finger-post so faint as to be passed unnoticed by other eyes, but sufficiently warning to his clearer vision to cause him to pause midway in the broad track of circumstantial evidence and look around him for a concealed path.
It was the point he had mentioned to Caldew at his chambers after reading the copy of the coroner's depositions which Merrington had lent him. While perusing them he had been struck by a curious fact. The medical evidence stated that the cause of death was a small punctured wound not larger than a threepenny piece, but added the information that the hole in the gown of the dead woman was much larger, about the diameter of a half-crown. The Government pathologist had formed the opinion that the revolver must have been held very close to the body to account for the larger scorched hole. That inference was obvious, but Colwyn saw more in the two holes than that. It seemed to him that the live ring of flame caused by the close-range shot must have been extinguished by the murderer, or it would have continued to smoulder and expand in an ever-widening circle. And that thought led to another of much greater significance. The shot had been fired at close range to ensure accuracy of aim or deaden the sound of the report. But, whichever the murderer's intention, the second purpose had been achieved, intentionally or unintentionally. How had it happened, then, that the sound of the report had penetrated so loudly downstairs?