In his own car, the coroner drove us up the road in the direction of the New York state boundary to the spot where the body had been found. It was a fine, well-oiled road and I noticed the number and high quality of the cars which passed us.
When we arrived at the spot where the body of the unfortunate girl had been discovered, Garrick began a minute search. I do not think for a moment that he expected to find any weapon, or even the trace of one. It seemed hopeless also to attempt to pick out any of the footprints. The earth was soft and even muddy, but so many feet had trodden it down since the first alarm had been given that it would have been impossible to extricate one set of footprints from another, much less to tell whether any of them had been made by the perpetrators of the crime.
Still, there seemed to be something in the mud, just off the side of the road, that did interest Garrick. Very carefully, so as not to destroy anything himself which more careless searchers might have left, he began a minute study of the ground.
Apparently he was rewarded, for, although he said nothing, he took a hasty glance at the direction of the sun, up-ended the camera he had brought, and began to photograph the ground itself, or rather some curious marks on it which I could barely distinguish.
The coroner and I looked on without saying a word. He, at least, I am sure, thought that Garrick had suddenly taken leave of his senses.
That concluded Garrick's investigation, and, after thanking the coroner, who had gone out of his way to accommodate us, we started back to town.
"Well," I remarked, as we settled ourselves for the tedious ride into the city in the suburban train, "we don't seem to have added much to the sum of human knowledge by this trip."
"Oh, yes, we have," he returned, almost cheerfully, patting the black camera which he had folded and slipped into his pocket. "We'll just preserve the records which I have here. Did you notice what it was that I photographed?"
"I saw something," I replied, "but I couldn't tell you what it was."
"Well," he explained slowly as I opened my eyes wide in amazement at the minuteness of his researches, "those were the marks of the tire of an automobile that had been run up into the bushes from the road. You know every automobile tire leaves its own distinctive mark, its thumb print, as it were. When I have developed my films, you will see that the marks that have been left there are precisely like those left by the make of tires used on Warrington's car, according to the advertisement sent out by McBirney. Of course, that mere fact alone doesn't prove anything. Many cars may use that make of tires. Still, it is an interesting coincidence, and if the make had been different I should not feel half so encouraged about going ahead with this clew. We can't say anything definite, however, until I can compare the actual marks made by the tires on the stolen car with these marks which I have photographed and preserved."