No doubt the basement could be reached in some way from the floor above, and any unusual sound below might easily attract attention.
In the intensity of the gloom, his sense of direction failed, taking him somewhat further back before he finally located the exact position of those outer steps.

Then as he turned abruptly, his foot came in contact with an obstacle on the floor.

For an instant he could not determine what it was; then, with a thrill of horror, he realized the presence of a human body.

There was no sound, no movement, and West drew back from contact with the object, shrinking in horror.

Then he gripped himself sternly--whoever, whatever this was, he must know.