"An alley-way," replied Mr. Allen.
"Opening on the next street?"
"Yes."
"Then these marks add a new feature to the case," said Parker. "Has anybody been through the window to your knowledge?"
Every one shook his head.
"Queer," said Mr. Sumner. "If the thief came through the window how did he know the combination of the safe?"
"I have it," said Hamington. "You often opened the safe during the daytime, did you not?"
"Yes."
"Then the would-be thief watched you from the window. By looking from the left side he could easily see you work the combination without being seen himself. He watched you until he was sure he had the combination down fine, and last night he opened the window, stepped inside, opened the safe and took out the tin box, closed the door again, and escaped as he had come."