Nick unlocked the desk, and, rolling the top partly up, he began a careful inspection of the brass socket which received the bolt of the lock when the desk was securely closed. He found several tiny, faint scratches on one side of it, which could not have been caused by the action of the bolt, not being where it came in contact with the socket. An examination with a powerful lens, moreover, showed that these slight marks were quite bright, as if recently made and with an instrument as sharp as the point of a pin.
Nick returned the ring of keys and resumed his seat.
“That lock has recently been picked, Mantell,” he said confidently.
“Picked!” Mantell exclaimed amazedly. “Are you sure of it?[Pg 18]”
“Positively.”
“But——”
“There aren’t any buts,” Nick interrupted. “I know when evidence shows that a lock has been picked. The crook who picked that one used a tool with a sharp point, which at times touched one side of the bolt socket and left faint marks in the brass. The brightness of them shows that it was quite recently done.”
“But our servants are entirely trustworthy, Nick, and——”
“I don’t think it was done by one of your servants,” Nick again interrupted. “Have you a burglar alarm in the house?”
“Yes, an electric alarm,” said Mantell. “All of the doors and windows on the ground floor are protected. Perkins, the butler, sets it each night before he retires.”