“No, it isn’t!” cried Swain, his face livid.  “It isn’t possible!  I’m not a murderer.  I remember everything else—­do you think I wouldn’t remember a thing like that!”

“I don’t know what to think,” Godfrey admitted, a straight line between his brows.  “Besides, there’s the handkerchief.”

“I don’t see any mystery about that,” said Swain.  “There’s only one way that could have come there.  It dropped from my wrist when I stooped over Miss Vaughan.”

Godfrey looked at me, and I nodded.  Swain might as well know the worst.

“That would be an explanation, sure enough,” said Godfrey, slowly, “but for one fact—­you didn’t have any bandage on your wrist when you came back over the wall.  Both Lester and I saw your wrist and the cut on it distinctly.  Therefore, if you dropped the handkerchief there, it must have been before that.”

The blood had run from Swain’s cheeks, as though drained by an open artery, and for a moment he sat silent, staring at the speaker.  Then he raised his trembling right hand and looked at it, as though it might bear some mark to tell him whether it were indeed guilty.

“But—­but I don’t understand!” he cried thickly.  “You—­you don’t mean to intimate—­you don’t believe—­but I wasn’t unconscious, I tell you!  I wasn’t near the house until after we heard the screams!  I’m sure of it!  I’d stake my soul on it!”

“Get a grip of yourself, Swain,” said Godfrey, soothingly.  “Don’t let yourself go like that.  No, I don’t believe you killed Worthington Vaughan, consciously or unconsciously.  I said Goldberger’s theory was a good one, and it is; but I don’t believe it.  My belief is that the murder was done by the Thug; but there’s nothing to support it, except the fact that he was on the ground and that a noose was used.  There’s not a bit of direct evidence to connect him with the crime, and there’s a lot of direct evidence to connect you with it.  It’s up to us to explain it away.  Now, think carefully before you answer my questions:  Have you any recollection, however faint, of having seen Mahbub before this morning?”

Swain sat for quite a minute searching his consciousness.  Then, to my great disappointment, he shook his head.

“No,” he said; “I am sure I never saw him before.”

“Nor Silva?”

“No, nor Silva—­except, of course, the time, three or four months ago, when he gave me Mr. Vaughan’s message.”

“Have you a distinct recollection that the library was empty when you sprang into it?”

“Yes; very distinct.  I remember looking about it, and then running past the table and discovering Miss Vaughan.”

“You saw her father also?”

“Yes; but I merely glanced at him.  I realised that he was dead.”

“And you also have a distinct recollection that you did not approach him or touch him?”

“I am quite certain of that,” answered Swain, positively.