He ran across the station into the refreshment room, went out by the other door and sprang into a cab:
"Drive to the Rue Clapeyron."
After making sure that he was not being followed, he stopped the cab at the commencement of the street and began to make a careful examination of the house in which Maître Detinan lived and of the two adjoining houses. He paced off certain distances and noted the measurements in his memorandum book:
"Now drive to the Avenue Henri-Martin."
He dismissed his cab at the corner of the avenue and the Rue de la Pompe, walked along the pavement to No. 134 and went through the same performance in front of the house which Baron d'Hautrec had occupied and the two houses by which it was hemmed in on either side, measuring the width of their respective frontages and calculating the depth of the little gardens in front of the houses.
The avenue was deserted and very dark under its four rows of trees, amid which an occasional gas-jet seemed to struggle vainly against the thickness of the gloom. One of these lamps threw a pale light upon a part of the house and Shears saw the notice "To Let" hanging on the railings, saw the two neglected walks that encircled the miniature lawn and the great empty windows of the uninhabited house.
"That's true," he thought. "There has been no tenant since the baron's death.... Ah, if I could just get in and make a preliminary visit!"
The idea no sooner passed through his mind than he wanted to put it into execution. But how to manage? The height of the gate made it impossible for him to climb it. He took an electric lantern from his pocket, as well as a skeleton key which he always carried. To his great surprise, he found that one of the doors of the gate was standing ajar. He, therefore, slipped into the garden, taking care not to close the gate behind him. He had not gone three steps, when he stopped. A glimmer of light had passed along one of the windows on the second floor.
And the glimmer passed along a second window and a third, while he was able to see nothing but a shadow outlined against the walls of the rooms. And the glimmer descended from the second floor to the first and, for a long time, wandered from room to room.
"Who on earth can be walking about, at one in the morning, in the house where Baron d'Hautrec was murdered?" thought Shears, feeling immensely interested.