"I wouldn't doubt your word for an instant," said Pendleton, in something like his old voice. "Whatever it is, I'm quite sure it is if you say so."
The policeman on guard in the hall examined them carefully.
"All right," said he, after they had explained and he had verified it by calling to his mate at the street door. "Go right to work, gents. I'm here to see that nobody gets in from above by way of the scuttle, and I guess I won't be in the way."
There were three gas branches at intervals along the length of the dim hall, each with a cluster of four jets. Ashton-Kirk lighted all three of these and began making a careful examination of the passage. Along toward the rear was a stairway leading to the floor above. Next this was a small room in which there was a water tap. At the extreme end of the hall was a window with a green shade drawn to the bottom.
Ashton-Kirk regarded this for a moment intently. Then he reached up and turned off the gas at the branch nearest the window. Daylight could now be seen through the blind; the investigator pointed and said:
"This shows us something. About six inches of the bottom of the blind is of a decidedly lighter color than the remainder. This is caused by exposure to the light and indicates that this blind has seldom been drawn in daylight as it is now."
He drew back the blind and looked at the side nearest the window. At the top of the faded space was a heavy dark line.
"I'll modify that last statement," said he, with satisfaction. "I'll go as far as to say, now, that the blind has never been drawn since it was put up. This thick line marks the part that lay across the top of the roller, and the dust seems never to have been disturbed."
The gas was lighted once more.
"Hume did not draw that curtain," said Ashton-Kirk, decidedly. "He was too careless a man, apparently, to think of such a thing. The intruders, whoever they were, did it; they had a light, perhaps, and did not want to be—"