As he was turning these matters over in his mind, Mrs. Stevens and her daughter entered the room.
"What have you discovered, Mr. Carter?" asked the girl. "You must know that my mother has told me all about this strange affair, and I am deeply interested."
"I have learned nothing," said Nick, "except that this room can be easily entered, even when the doors are locked.
"Take this door leading to the rear room, for instance. The key was on this side, it is true, but it turns very easily. A person with a pair of nippers could get in without trouble, and lock the door afterward.
"I can't tell from the appearance of the key whether or not this was done, but I think it probable."
"You mean that somebody came in here while mother was at lunch, and put the jewels where they were found?"
"Exactly."
"But who could it have been?"
"I don't know," answered Nick, frankly.
"And how do you explain the presence of that other pin in the box?" asked Mrs. Stevens.