"Then why suspect your visitor of being a ghost?"
"Because," Alsop said patiently, "this visitor had every appearance of walking through a locked door."
Nora alone was thoroughly impressed.
"Tell us," she urged.
"I've a safe in my room," Alsop said, "and as an extra precaution, when I've had important papers at the house, I've locked my door. I went upstairs late last night. There was no light in the upper hall, but a glow came from the lamps downstairs. In this sort of radiance I saw the figure of a woman, clothed in white, her face hidden behind a white veil, come apparently from my room, cross the hall, and disappear. I cried out. I sprang for the door. It was locked. Marvin and I searched the house. My daughters are in Florida. The only women in the place were servants. There seemed no way in or out of the house without the collusion of one of these. And I've had them a long time. It's hard to suspect them. Besides, Marvin has had much the same experience. Tell them, Arthur."
"As a motive," Marvin said slowly, "I might mention the fact that I often take my work upstairs—letters of Mr. Alsop's to answer, statements to make out. The first time the thing happened was Thursday night. It must have been after midnight. I was in bed. I awakened with that uncomfortable feeling of being no longer alone. At first I saw nothing. The only light in the room came from a dying moon. I had been nervous for several nights, fearing an attempt on Mr. Alsop. I never could get him to take that very seriously until to-day. At any rate, after a long time, I saw this figure that Mr. Alsop describes. It did not seem to come from anywhere."
He commenced to pace up and down the room. There was about the sudden gesture of his hand a despairing belief that shocked Garth.
"The thing—white veil and all—seemed to materialize out of nothing. It moved softly about the room as if searching—searching. I thought of the letters on my desk. I called out instinctively, 'Who's there?' There was no reply. The figure did not hurry. It stepped behind a screen by the fireplace. I sprang up and went there. I couldn't believe the evidence of my eyes. There was no one—nothing behind the screen. I examined the door. It was locked as I had left it, with the key on the inside. There was no way in or out of that room. Yet the veiled woman had been there, and had gone, leaving no trace."
"The windows," Garth said, "or the fireplace?"
Marvin shook his head.