on the right-hand side, was the stairway leading to the floors above; and directly beyond the stairway, also on the right, was a small reception-room with a wide archway instead of a door. Directly opposite to the stairway, in a small recess, stood the telephone switchboard. There was no elevator in the house.
Another important feature of this ground-floor plan was a small passageway at the rear of the main hall and at right angles to it, which led past the front walls of the Odell apartment to a door opening on a court at the west side of the building. This court was connected with the street by an alley four feet wide.
In the accompanying diagram this arrangement of the ground floor can be easily visualized, and I suggest that the reader fix it in his mind; for I doubt if ever before so simple and obvious an architectural design played such an important part in a criminal mystery. By its very simplicity and almost conventional familiarity—indeed, by its total lack of any puzzling complications—it proved so baffling to the investigators that the case threatened, for many days, to remain forever insoluble.
As Markham entered the Odell apartment that morning Sergeant Ernest Heath came forward at once and extended his hand. A look of relief passed over his broad, pugnacious features; and it was obvious that the animosity and rivalry which always exist between the Detective Division and the District Attorney's office during the investigation of any criminal case had no place in his attitude on this occasion.
"I'm glad you've come, sir," he said; and meant it.
