"For the past few years, of course, every real villain has had to have at least a touch of Teutonic blood to account for the various treacheries which he tackles. I don't recall a single novel—or a short story, either—that has had an English or French villain who is foiled in the last few pages. I suppose you'd call it the entente cordiale of the novelists, a sort of concerted attempt by the writing clan to do their bit against the Hun. And mighty good propaganda it was, too....
"But, unfortunately, the detective of real life can't always tell by determining a man's nationality whether he's going to turn out to be a crook or a hero. When you come right down to it, every country has about the same proportion of each and it's only by the closest observation that one can arrive at a definite and fact-supported conclusion.
"Details—trifles unnoticed in themselves—play a far larger part in the final dénouement than any preconceived ideas or fanciful theories. There was the case of Ezra Marks and the Dillingham diamonds, for example...."
Ezra [continued the former Secret Service operative, when he had eased his game leg into a position where it no longer gave him active trouble] was all that the name implied. Born in Vermont, of a highly puritanical family, he had been named for his paternal grandfather and probably also for some character from the Old Testament. I'm not awfully strong on that Biblical stuff myself.
It wasn't long after he grew up, however, that life on the farm began to pall. He found a copy of the life of Alan Pinkerton somewhere and read it through until he knew it from cover to cover. As was only natural in a boy of his age, he determined to become a great detective, and drifted down to Boston with that object in view. But, once in the city, he found that "detecting" was a little more difficult than he had imagined, and finally agreed to compromise by accepting a very minor position in the Police Department. Luckily, his beat lay along the water front and he got tangled up in two or three smuggling cases which he managed to unravel in fine shape, and, in this way, attracted the attention of the Customs Branch of the Treasury Department, which is always on the lookout for new timber. It's a hard life, you know, and one which doesn't constitute a good risk for an insurance company. So there are always gaps to be filled—and Ezra plugged up one of them very nicely.
As might have been expected, the New Englander was hardly ever addressed by his full name. "E. Z." was the title they coined for him, and "E. Z." he was from that time on—at least to everyone in the Service. The people on the other side of the fence, however, the men and women who look upon the United States government as a joke and its laws as hurdles over which they can jump whenever they wish—found that this Mark was far from an easy one. He it was who handled the Wang Foo opium case in San Diego in nineteen eleven. He nailed the gun runners at El Paso when half a dozen other men had fallen down on the assignment, and there were at least three Canadian cases which bore the imprint of his latent genius on the finished reports.
His particular kind of genius was distinctly out of the ordinary, too. He wasn't flashy and he was far from a hard worker. He just stuck around and watched everything worth watching until he located the tip he wanted. Then he went to it—and the case was finished!
The chap who stated that "genius is the capacity for infinite attention to details" had Ezra sized up to a T. And it was one of these details—probably the most trifling one of all—that led to his most startling success.
Back in the spring of nineteen twelve the European agents of the Treasury Department reported to Washington that a collection of uncut diamonds, most of them rather large, had been sold to the German representative of a firm in Rotterdam. From certain tips which they picked up, however, the men abroad were of the opinion that the stones were destined for the United States and advised that all German boats be carefully watched, because the Dillingham diamonds—as the collection was known—had been last heard of en route to Hamburg and it was to be expected that they would clear from there.