“So,” said Godfrey slowly, “it couldn’t have been dropped there by Swain when he stooped to pick her up.”

“No; besides, we know perfectly well that it wasn’t about his wrist when he came back over the wall.  Goldberger knows it, too, and we’ll be asked about it, next time.”

“It might have been pushed up his sleeve—­we weren’t absolutely certain.  But this new evidence settles it.”

I assented miserably and Godfrey smoked on thoughtfully.  But my cigar had lost some of its flavour.

“How did Miss Vaughan come to find the body?” he asked at last, and I told him the story as she had told it to me.  He thought it over for some moments; then he leaned forward and laid his hand on my knee.

“Now, Lester,” he said, “let’s review this thing.  It can’t be as dark as it seems—­there’s light somewhere.  Here is the case, bared of all inessentials:  Swain crosses the wall about eleven o’clock, cutting his wrist as he does so; Miss Vaughan meets him about eleven-thirty, and after a time, finds that his wrist is bleeding and ties her handkerchief about it; they agree to have her father examined for lunacy, arrange a meeting for the next night, and are about to separate, when her father rushes in upon them, savagely berates Swain and takes his daughter away.  That must have been about twelve o’clock.

“Swain, according to his story, sits there for ten or fifteen minutes, finally sees the cobra, or thinks he does, and makes a dash for safety, striking his head sharply against a tree.  He tumbles over the wall in a half-dazed condition.  The handkerchief is no longer about his wrist.  That, you will remember, was about twelve-twenty.

“Almost at once we heard Miss Vaughan’s screams.  After that, Swain isn’t out of our sight for more than a minute—­too short a time, anyway, for anything to have happened we don’t know about.

“Meanwhile, Miss Vaughan has returned with her father to the house, hearing steps behind her and taking it for granted that it is Swain following at a distance.  She goes to her room, stays there fifteen minutes or so, and comes downstairs again to find her father dead.

“Now let us see what had happened.  You were right in saying that her father must have been strangled immediately after she left him.  Otherwise he would still have been twitching in such a way that she must have noticed it.  No doubt he dropped into the chair exhausted by his fit of rage; the murderer entered through the garden door, stopped to cut off the end of the curtain-cord and make a noose of it—­that would have taken at least a minute—­and then strangled his victim.  Then he heard her coming down the stairs, and escaped through the garden-door again just as she entered at the other.  She saw the curtain still shaking.  Then she fainted.

“Now, what are the clues to the murderer?  A string tied with a peculiar knot, the blood-stained handkerchief, and the finger-prints on the dead man’s robe.”