Part 31 (2/2)
”s.h.i.+rley?”
”Exactly! And there is still another possibility.”
”What is that?”
”Here in this laboratory I have blood spots made on the portieres at the house of Phelps by the man who removed the needle, probably the unknown himself, possibly his--or her--agent. In any case it is a clue and--THE ONLY DIRECT AND INFALLIBLE CLUE IN EXISTENCE TO THE CRIMINAL!
Also I have the evidence of the snake venom and of the botulin toxin here. Sooner or later the person who killed Werner because he suspected things will wake up to the fact that we possess tangible proof against him.”
I grew pale. ”You mean, then, that you may be attacked yourself? That even I--”
Kennedy smiled, unafraid. But from the expression in his eyes I knew that he took the thought of our possible danger very seriously.
XXIV
THE INVISIBLE MENACE
Mackay and I exchanged glances. Kennedy busied himself putting away some of the more important bits of evidence in the case, placing the tiny tubes of solution, the blood smears, and other items together in a cabinet at the farther corner of the laboratory. The vast bulk of his paraphernalia, the array of gla.s.s and chemicals and instruments, he left on the table for the morning. Then he faced us again, with a smile.
”Suppose you start up the percolator once more, Walter!” He took a cigar and lighted it from the match I struck. ”I believe I've earned another cup of coffee,” he added.
Mackay had been fidgeting considerably since Kennedy's explanation of the possible danger to s.h.i.+rley, as well as to ourselves or even to others.
”Isn't there something we can do, Kennedy?” he exclaimed, suddenly. ”Is it necessary to sit back and wait for this unknown to strike again?”
”Ordinarily,” Kennedy replied, ”on a case like this it has been my custom to permit the guilty parties to betray themselves, as they will do inevitably--especially when I call to my aid the recent discoveries of science for the detection and measurement of fine and almost imperceptible shades of emotion. But now that I realize the presence of this menace I shall become a detective of action; in fact, I shall not stop at any course to hurry matters. The very first thing in the morning I shall go to the studio and I want you and Jameson along.
I”--his eyes twinkled; it was the excitement at the prospect--”I may need considerable help in getting the evidence I wish.”
”Which is--?” It was I who interposed the question.
Kennedy blew a cloud of smoke. ”There are three ways of tracing down a crime, aside from the police method of stool pigeons to betray the criminals and the detective bureau method of cross-examination under pressure, popularly known as the third degree.”
”What are they?” Mackay asked, unaware that Kennedy needed little prompting once he felt inclined to talk out some matter puzzling him.
”One is the process of reasoning from the possible suspects to the act itself--in other words, putting the emphasis on the motive. A second is the reverse of the first, involving a study of the crime for clues and making deductions from the inevitable earmarks of the person for the purpose of discovering his ident.i.ty. The third method, except for some investigations across the water, is distinctly my own, the scientific.
”In all sciences,” Kennedy went on, warming to his subject, ”progress is made by a careful tabulation of proved facts. The scientific method is the method of exact knowledge. Thus, in crime, those things are of value to us which by an infinite series of empiric observations have been established and have become incontrovertible. The familiar example, of course, is fingerprints. Nearly everyone knows that no two men have the same markings; that the same man displays a pattern which is unchanging from birth to the grave.
”No less certain is the fact that human blood differs from the blood of animals, that in faint variations the blood of no two people is alike, that the blood of any living thing, man or beast, is affected by various things--an infinite number almost--most of which are positively known to modern medical investigators.
”In this case my princ.i.p.al scientific clue is the blood left upon the portiere by the man who took the needle the night following the murder.
Next in importance is the fact, demonstrated by me, that some one at the studio wiped a hypodermic on a towel after inoculating himself with antivenin. Of course I am presuming that this latter man inoculated himself and not some one else, because it is obvious. If necessary I can prove it later, however, by a.n.a.lyzing the trace of blood. That is not the point. The point is that whoever removed the needle p.r.i.c.ked himself and yet did not die of the venom--unless it was a person not under our observation, an unlikely premise. Therefore, because of this last fact, and because again it is obvious, I expect to find that the same individual inoculated himself with antivenin and removed the needle from the portiere; and I expect to prove it beyond possibility of doubt by an a.n.a.lysis of his blood. A sample of the blood from this person will be identical with the spot on the portiere, and--much the easier test--will contain traces of the ant.i.toxin.
”With that much accomplished, a little of the, well--third degree, will bring about a confession. It is circ.u.mstantial evidence of the strongest sort. Not only does a man take precautions against a given poison, but he is proved to be the one who removed the needle actually responsible for Miss Lamar's death.
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