"Nicolas, I want you to wait here," said Hanaud. "If the door is opened, whistle for us and keep it open."
"Very well, sir."
Hanaud said in a low and troubled voice to Frobisher: "There is something here which alarms me." He dived into a narrow alley at the side of the shop.
"It was in this alley no doubt that Waberski meant us to believe that he hid on the morning of the 7th of May," Jim whispered as he hurried to keep with his companion.
"No doubt."
The alley led into a lane which ran parallel with the street of Gambetta. Hanaud wheeled into it. A wall five feet high, broken at intervals by rickety wooden doors, enclosed the yards at the backs of the houses. Before the first of these breaks in the wall Hanaud stopped. He raised himself upon the tips of his toes and peered over the wall, first downwards into the yard, and then upwards towards the back of the house. There was no lamp in the lane, no light showing from any of the windows. Though the night was clear of mist it was as dark as a cavern in this narrow lane behind the houses. Jim Frobisher, though his eyes were accustomed to the gloom, knew that he could not have seen a man, even if he had moved, ten yards away. Yet Hanaud still stood peering at the back of the house with the tips of his fingers on the top of the wall. Finally he touched Jim on the sleeve.
"I believe the back window on the first floor is open," he whispered, and his voice was more troubled than ever. "We will go in and see."
He touched the wooden door and it swung inwards with a whine of its hinges.
"Open," said Hanaud. "Make no noise."
Silently they crossed the yard. The ground floor of the house was low. Jim looking upwards could see now that the window above their heads yawned wide open.