“No, sir.[{18}]”
“Did you lock the door after going out with your companions?”
“That was not necessary,” Oakley explained. “It has an automatic spring lock, like many of the doors in this building, which can be opened from within, though a key is required by one entering from outside. They were equipped with locks of that kind because students frequently are the last to leave the building, and it obviated providing keys for all.”
“I see,” Nick remarked. “One can leave this basement without a key, then?”
“Yes, sir; easily.”
Nick took out his electric searchlight and began a close inspection of the cement floor. It was covered with a thin, almost imperceptible layer of dust, mingled with which were particles of coal dust, quite plainly visible with the aid of a powerful lens.
“You have given it to me straight, Oakley, all right,” Nick remarked, after a moment, looking up. “My lens shows where the dust has been disturbed, and I can determine part of the outline of the body. There appears to have been considerable moving about, however, either by——”
“Surely not by the body!” Oakley exclaimed, staring.
“Don’t be so sure of that,” Nick said dryly. “Things aren’t always what they seem. We may find that—ah, I find it even sooner than I expected. Here is one—yes, a second and third. This tells the story.”
“What is it?” cried Oakley impulsively.