"I can imagine a theory," Stone responded, "but it is merely a theory--a surmise, rather; and it is so doubtful, at best, I'd rather not divulge it at present. But the pin must be found." "I haven't found it, but I've a notion of which way to look," said Fibsy, who had just entered the room. It was Mrs. Pell's sitting room, and Fleming Stone was still fingering some packets of papers in the desk. "Out with it, Fibs, for I'm going over to see Mr. Bannard now, and I want all your information before I go." So Fibsy told of what Sam had said, and of the snatch of song he had sung. "Good enough as far as it goes," commented Stone, "but your source of knowledge seems a bit uncertain." "That's just it," said Fibsy. "That's why I didn't tell you this last night. I thought I'd tackle friend Boobikins this morning and see if I could get more of the real goods. But, nixie. Sam says he has the pin, but he doesn't know where it is." "I'm afraid you're trying to draw water from an empty well, son; better try some other green fields and pastures new." "I know it, Mr. Stone, but s'pose you just speak to the innocent before you go away. You can tell if he knows anything." "Why should Sam steal the pin?" Iris asked, her eyes big with amazement. "You can't tell _what_ such people will do," Fibsy returned. "He may have seen you hiding it, as he says he did, and he may have come in and stolen it, just because of a mere whimsey in his brain. Is he around here much?" "Quite a good deal, of late. He's fond of Agnes, and he trails her about, like a dog after its master. Aunt Ursula wouldn't have him around much when she was here, but Miss Darrel doesn't mind." "I don't like him," said Lucille, "but I am sorry for him, and he does adore Agnes. I think he ought to be put in an institution." "Oh, no," said Iris, "he isn't bad enough for that. He's not really insane, just feeble-minded. He's perfectly harmless." "Bring him in here," suggested Stone. Fibsy ran out, and came back with the half-witted boy. "Hello, Sam," said Stone, in an off-handed, kindly way, "you're the boy for us. Now, where did you say you found that pin?" "Here," and Sam pushed his hand down in the big chair, in the very spot where Iris had concealed it. "Good boy! How'd you get in this room?" "Through window in other room--walked in here!" He spoke with pride in his achievement. But at Stone's next question, a look of deep cunning came into his eyes, and he shook his head. For the detective said, "Where is the pin now, Sam?" The lack-luster eyes gleamed with an uncanny wisdom, and the stupid face showed a stubborn denial, as he said, "I donno, I donno, I donno." And then he broke forth again into the droning song: "It is a sin to steal a pin, As well as any greater thing!" This couplet he repeated, in his peculiarly insistent way, until they were all nearly frantic. "Stop that!" ordered Lucille. "Put him out of the room, somebody. Hush up, Sam!"