“A possible solution came to me from memory of a detective story2 I once read, in which the murderer, something of a practical scientist, made, by means of an ingenious and practicable photographical process, a die of another’s man’s thumbprint. This he used to incriminate the innocent owner of the thumb.
“For a while I cherished this theory, so vivid was my recollection of the possibility of the method; but I was never really satisfied. Then, suddenly, I found the explanation which I was afterwards to prove true.
“Instead of going to the immense trouble of making a stamp or die, why not obtain beforehand upon the desired object the actual fingerprints of the chosen scapegoat?
“After consideration, I accepted this idea. It fitted well enough with my murderer—a fellow of infinite cunning. I proceeded with the work of reconstruction. Thus:—
“Since Deacon had no knowledge of the crime, the murderer must have induced him, in circumstances so ordinary or usual as to be likely to escape his memory, to take hold of the wood-rasp by its handle at some time before the murder; perhaps eight hours, probably not more. For this clever murderer would realise the difficulty of retaining the fingerprints unspoiled.
“When, after obtaining the fingerprints, he had got rid of Deacon, he must have removed with gloved hands—taking care not to touch those parts of the handle where the prints must be—the handle he had loosened before Deacon had held it. Then that handle must have been packed (say in a small box with cork wedges) in such a way as to ensure that its carriage in the pocket for the descent of the wall and subsequent activities could be effected without those beautiful marks being spoiled. The reassembling of the tool must have been done after the murder; and the whole Deacon-damning bit of evidence then planted for the police to find.
“In the study, on a later visit, I found confirmation of the accuracy of my deductions. It will be remembered that when the wood-rasp was produced at the inquest, it was proved to the satisfaction of the court that it was indeed the weapon which had caused Hoode’s death. This proof lay preeminently in the condition of the blade, which was far from nice. But it was also pointed out by the police, to make the jury’s assurance doubly sure, that on a little rosewood table in the study there was a scar on the polish, known not to have existed before, which had obviously been made by the blade of just such a wood-rasp as this wood-rasp. Superintendent Boyd gave it as his opinion that the murderer had laid the wood-rasp on this table after he had killed Hoode, and while he was arranging the appearance of a struggle.
“I agree with the superintendent—but only up to a point. Where he was wrong was in assuming that the scar had been made by the murderer having put down on the table the whole wood-rasp.
“That scar is of exactly the same length as the blade of the rasp, and is in the centre of the table, having on every side of it some six inches of unscarred tabletop.
“Do you see? That scar could not have been made by the complete tool! The handle is two and a half to three inches in circumference, and if it had been joined to the blade would, by reason of its far greater thickness, have allowed no more than an inch or so of the blade’s tip to touch and scar the table. Had the complete rasp been laid down at an edge of the table with the handle projecting into space, the full-length scar would have been possible. But the scar, as I have described, is in the middle of the table, and could therefore only have been made by the blade without its handle.
“Here, then, was the justification of my theory. Further proof came later. With full official permission I examined the wood-rasp. It was as it had been found. I held it in my hand. I shook it—and the blade flew off. Two small wooden wedges fell to the floor. I picked a shred of linen from the tang of the blade.
“Obviously, the use of the little wedges had been to hold the tang of the blade in the enlarged socket of the handle. And the fact that the socket had been enlarged, added to the inadequacy of the wedges, is surely proof enough that the blows which killed Hoode were struck with the blade alone. There is, however, yet more—the shred of linen. It came, I should say, from a handkerchief, the use of which had been, I take it, to get a better grip of the thin tang when striking. The glove the murderer was undoubtedly wearing probably proved insufficient to ensure against a slipping grip. So he wrapped a handkerchief about his gloved hand. An inequality in the surface of the steel caught some loose thread. This he did not notice when hastily ramming handle and blade together after the kill.
“The wedges and the shred of linen are in the keeping of Superintendent Boyd, to whom I gave them at the time of my discovery. I could not, my case being incomplete, explain then their significance.
“My next step was to question Deacon. To my surprise and consternation I found that although he was a man for whom tools had neither interest nor meaning and for whom therefore the handling of any such implement might be so much out of the ordinary as to impress itself upon his memory, he had no recollection of ever seeing, before the inquest, any wood-rasp. He even suggested that until now he had not known such a tool to exist.
“I will not deny that Deacon’s emphatic assertion that he had never even seen the rasp until it was exhibited at the inquest gave me a shaking. It did, and a bad one. I tested all the links in my chain, only
