"Not the slightest. As you will note, they were mailed either at the central post office or at the railroad station--places so public that it's impossible to keep a strict watch for the person who mailed 'em. In one case--that of the Osgoods--we cautioned the wife to say nothing whatever about the matter, and then ordered every clerk in the post office to look out for letters in that handwriting which might be slipped through the slot. In fact, we closed all the slots save one and placed a man on guard inside night and day." "Well, what happened?" inquired Allison, a trifle impatiently, as the postmaster paused. "The joke was on us. Some two days later a letter which looked suspiciously like these was mailed. Our man caught it in time to dart outside and nail the person who posted it. Fortunately we discovered that she was Mrs. Osgood's sister-in-law and that the letter was a perfectly innocent one." "No chance of her being mixed up in the affair?" "No. Her husband is a prominent lawyer here, and, besides, we've watched every move she's made since that time. She's one of the few people in town that we're certain of." "Yet, you say her handwriting was similar to that which appears on these letters?" "Yes, that's one of the many puzzling phases of the whole matter. Every single letter is written in a hand which closely resembles that of a relative of the person to whom it is addressed! So much so, in fact, that at least four of the complainants have insisted upon the arrest of these relatives, and have been distinctly displeased at our refusal to place them in jail merely because their handwriting is similar to that of a blackmailer." "Why do you say blackmailer? Do you know of any demand for money which has been made?" "Not directly--but what other purpose could a person have than to extract money? They'd hardly run the risk of going to the pen in order to gratify a whim for causing trouble." "How about the Tysons and the Osgoods and the other people who brought these letters in--didn't they receive subsequent demands for money?" "They received nothing--not another single letter of any kind." "You mean that the simple fact of making a report to your office appeared to stop the receipt of the threats." "Precisely. Now that you put it that way, it does look odd. But that's what happened." Allison whistled. This was the first ray of light that had penetrated a very dark and mysterious case, and, with its aid, he felt that he might, after all, be successful. Contenting himself with a few more questions, including the names of the couples whom gossip stated had been separated through the receipt of anonymous communications, Allison bundled the letters together and slipped them into his pocket.