"You don't know, then, whether the person he seemed to expect ever turned up?"
Beverley shook her head. "Roger and I went straight ahead to a newsstand where I expected to meet a person. Two or three minutes after we passed O'Reilly we were mixed up in a big crowd, almost fighting our way through...."
"Oh, a big crowd!" Clo broke in. "A chance for that pickpocket. Suppose he came the minute you had turned your backs on O'Reilly, and he sent his trained thief after you, hot foot, to get that envelope?"
"Ah, but you've forgotten something!" cried Beverley. "A thief might get the envelope: I'll admit that. But how could he have another one exactly like it, with the same seals, the same monogram, to put into Roger's pocket, when he took the original?"
"He could only have it if O'Reilly could have given it to him. Could he have done that?"
Suddenly Beverley began to see. A vivid idea sprang into her head, and was imaged in her eyes.
"You've thought of something!" Clo exclaimed. "You see how O'Reilly might have got the seal with the monogram, and the gold wax, and an envelope like the one you had?"
"Oh, yes. I do see!" Beverley groaned. "He could have brought the things from—from.... But never mind. That part's nothing to you."
"I want only to know the part you want me to know," said Clo.
"It isn't a question of what I want. It's a question of my sacred oath," Beverley answered. "There was a house where I had been, to get the envelope. O'Reilly was there, too. Someone ... no matter who! ... could have given him all the things, so he could change envelopes if he got the chance. Oh, child, I keep stumbling on to a path where I dare not step."