First one and then another of the drawers he pulled open; like those of the desk, they told of the same hasty hand. However, this seemed to be all they had to tell, for the secret agent did not spend more than an instant over each. But as he was about to open the last but one, Fuller saw him pause and bend nearer. Then out came a morocco case and from this was produced a powerful magnifying glass. It was the knob upon the left hand side of the drawer that had caught his attention; putting the lens on this it threw up a thick, dark splotch.
"In searching the body after the shooting," said he, "the fellow, whoever he was, probably came in contact with the flow from the wound. And in opening the drawer he transferred it to the knob."
"No," said he. "It is his own blood. Look!" and he ran the glass from knob to knob upon the other drawers; "there are no marks here. And yet a man making a search would invariably start at the top, as I have done." Then the lens shifted back to the knob with the splotch. "Mark this one closely," he added, "and tell me what you see."
"The knob has been broken," said Fuller at the first glance.
"Exactly. All along its top there is a keen ragged ridge. Probably seizing this to tear open the drawer, the criminal cut himself."
For a moment the speaker stood studying the broken knob with its particle of dried blood; then like a flash he turned to Fuller, his singular eyes ablaze, and snapped:
"On the desk there is a paper-weight. Get it."
Fuller, astonished, did as he was bidden.
"Throw it through a bookcase door," was Ashton-Kirk's astonishing reply.
"Throw it through a bookcase door," repeated the secret agent, busy with his lens.
Fuller stood a moment, hesitating; the other arose impatiently, took the heavy paper-weight from him and sent it crashing through the door of the nearest case. The glass splintered and fell jingling to the floor; Ashton-Kirk selected two small pieces and handed them to Fuller.
"In the kitchen you will find hot water and soap; wash and dry these carefully."
The assistant went hastily, and while he was gone, Ashton-Kirk bent once more over the broken knob. With the thin blade of a pocket-knife he picked at the fragment of dried blood; finally he worked it loose and caught it upon a card as it fell. Carrying this to a small table above which hung a light, he examined it carefully. Then to Fuller, as the latter returned, he said: