"Well," drawled Marks, "I trust he gets his satisfaction. Got any ideas on the matter?"
"Nary an idea. The stones were sold abroad and presumably they were headed for Hamburg—which would appear to point to a German boat. Four of them, supposedly—one of them, certainly—turned up here without passing through the office or paying the customary duty. Now go to it!"
When Marks got back to his hotel and started to think the problem over, he had to admit that there wasn't very much to "go to." It was the thinnest case he had ever tackled—a perfect circle of a problem, without the slightest sign of a beginning, save the one which was barred.
Anxious as he was to make good, he had to concede that the department's policy of working from the other end of the case was the right course to follow. He had heard of too many arrests that fell flat, too many weary weeks of work that went for nothing—because the evidence was insufficient—not to realize the justice of the regulations that appeared to hamper him.
"No," he thought, as he half dreamed over a pipe-load of tobacco, "the case seems to be impregnable. But there must be some way to jimmy into it if you try long enough."
His first move was the fairly obvious one of searching the newspaper files to discover just what ships had docked during the ten days previous to the appearance of the stones in Wheeling. But this led nowhere, because that week had been a very busy one in maritime circles. The Celtic, the Mauretania, the Kaiser Wilhelm der Grosse, the Kronprinzessin Cecelie, the Deutschland and a host of other smaller vessels had landed within that time.
Just as a check upon his observations, he examined the records for the week preceding the first appearance of the diamonds in New York. Here again he ran into a snag, but one which enabled him to eliminate at least half of the vessels he had considered before. However, there still remained a sufficient number to make it impossible to watch all of them or even to fix upon two or three which appeared more suspicious than the others.
The information from abroad pointed to the fact that a German boat was carrying the diamonds, but, Marks figured, there was nothing in the world to prevent the stones from being taken into England or France or Italy and reshipped from there. They had turned up in the United States, so why couldn't they have been slipped through the customs of other countries just as easily?
The one point about the whole matter that appeared significant to him was that two stones had been reported in each case—a pair in Wheeling and another pair in New York. This evidence would be translated either to mean that the smugglers preferred to offer the diamonds in small lots, so as not to center suspicion too sharply in their movements, or that the space which they used to conceal the stones was extremely limited.
Marks inclined to the latter theory, because two stones, rather than one, had been offered in each instance. If the whole lot had been run in, he argued, the men responsible would market them singly, rather than in pairs. This would not detract in the slightest from the value of the stones, as it isn't easy to match rough diamonds and thus increase their market value.