“Go ahead,” said Markham. “I’m listening.”
“To proceed, then. Another coincidence attached to these three sets of footprints. It was impossible, because of the dry, flaky nature of the snow, to determine whether the first set had originated in the house and returned there, or had first approached the house from the street and then retreated. Again, on the night of Chester’s demise, when the snow was damp and susceptible to clear impressions, the same doubt arose. The tracks to and from the house were on opposite sides of the front walk: not a single footstep overlapped! Accidental? Perhaps. But not wholly reasonable. A person walking to and from a door along a comparatively narrow pathway would almost certainly have doubled on some of his tracks. And even if he had failed to superimpose any of his footprints, the parallel spoors would have been close together. But these two lines of prints were far apart: each clung to the extreme edge of the walk, as if the person who made them was positively afraid of overlapping. Now, consider the footprints made this morning. There was a single line of them entering the house, but none coming out. We concluded that the murderer had made his escape via the front door and down the neatly swept walk; but this, after all, was only an assumption.”
Vance sipped his coffee and inhaled a moment on his cigarette.
“The point I’m trying to bring out is this: there is no proof whatever that all these footprints were not made by some one in the house who first went out and then returned for the express purpose of leading the police to believe that an outsider was guilty. And, on the other hand, there is evidence that the footprints actually did originate in the house; because if an outsider had made them he would have been at no pains to confuse the issue of their origin, since, in any event, they could not have been traced back farther than the street. Therefore, as a tentative starting-point, I assumed that the tracks had, in reality, been made by some one in the house.—I can’t say, of course, whether or not my layman’s logic adds lustre to the gladsome light of jurisprudence——”
“Your reasoning is consistent as far as it goes,” cut in Markham tartly. “But it is hardly complete enough to have led you directly to the linen-closet this morning.”
“True. But there were various contribut’ry factors. For instance, the galoshes which Snitkin found in Chester’s clothes-closet were the exact size of the prints. At first I toyed with the idea that they were the actual instruments of our unknown’s vestigial deception. But when, after they had been taken to Headquarters, another set of similar tracks appeared—to wit, the ones found this morning—I amended my theory slightly, and concluded that Chester had owned two pairs of galoshes—one that had perhaps been discarded but not thrown away. That was why I wanted to wait for Captain Jerym’s report: I was anxious to learn if the new tracks were exactly like the old ones.”
“But even so,” interrupted Markham, “your theory that the footprints emanated from the house strikes me as being erected on pretty weak scaffolding. Were there any other indicants?”
“I was coming to them,” replied Vance reproachfully. “But you will rush me so. Pretend that I’m a lawyer, and my summation will sound positively breathless.”
“I’m more likely to pretend that I’m a presiding judge, and give you sus. per coll.”
“Ah, well.” Vance sighed and continued. “Let us consider the hypothetical intruder’s means of escape after the shooting of Julia and Ada. Sproot came into the upper hall immediately after the shot had been fired in Ada’s room; yet he heard nothing—neither footsteps in the hall nor the front door closing. And, Markham old thing, a person in galoshes going down marble steps in the dark is no midsummer zephyr for silence. In the circumstances Sproot would have been certain to hear him making his escape. Therefore, the explanation that suggested itself to me was that he did not make his escape.”