"Yes," answered the superintendent, with a smile; "the reverend gentleman has great faith evidently in the infallibility of Uncle Sam’s post office; but his friend, Mr. Sammis, is not so trustful. After dropping the letter in the box, Mr. Moore went into the real-estate office to visit Sammis, who is a member of his church, and happened to mention sending the money; whereupon the real-estate man told him what a rash thing he had done to send money in that unsafe manner, and insisted that he should try to get the letter back. They came around here to stop the letter and have it registered before it went out. Of course, I consented to this. I told them that the man who attended to that box had not come in with the last collection, and asked them to wait until he arrived." The superintendent smiled grimly. "And now, here comes the mystery, Mr. Sheridan. When the carrier came in and we went to look for that letter, it wasn’t to be found. There was no pink envelope in his bag." "By Jove!" exclaimed Owen, who had not been in the secret service long enough to conceal his emotions. "We searched through the contents of the bag four times," Henderson went on. "We examined the bottom of the bag carefully, thinking it might possibly have stuck there; we went to the street letter box to see whether the pink envelope might not have been left behind. Not a trace of it could we find anywhere." "And Mr. Moore is quite certain that he dropped it in the box?" asked Owen. "Absolutely positive." "And quite sure that it was a pink envelope?" "Yes, he is certain of that." "Who’s the carrier who made the collections, Mr. Henderson?" "James Andrews." "‘Pop’ Andrews!" exclaimed Owen. "Then that disposes of the theory that the letter was stolen on the way from the street box to the post office. I’m sure that Pop is too honest to have stolen it himself, and too careful to let anybody else take it from his bag. What has Pop to say about the matter, Mr. Henderson?" "He hasn’t given us any explanation. He’s all broken up about the matter. The poor fellow realizes that he’s placed in a nasty position. Nevertheless, it seems to me that he’s holding something back. I mean to say that there’s something about his manner that sort of gives me the idea that he knows a little more than he cares to tell about that letter." "May I see him?" asked Inspector Sheridan. "Yes; I’ll send for him." Carrier Andrews entered the superintendent’s private office looking very worried and upset. He uttered an exclamation of astonishment when he discovered that Sheridan was the inspector assigned to the case. "Now, Pop," said Owen gently to the veteran postman, "what can you tell me about this pink letter? Any help that you can give me I’ll greatly appreciate."