We entered.  Nothing had been disturbed in the laboratory by the coroner and Kennedy was able to gain a complete idea of the case rapidly, almost as well as if we had been called in immediately.

Fortescue’s body, it seemed, had been discovered sprawled out in a big armchair, as Burke had said, by one of his assistants only a few hours before when he had come to the laboratory in the morning to open it.  Evidently he had been there undisturbed all night, keeping a gruesome vigil over his looted treasure house.

As we gleaned the meager facts, it became more evident that whoever had perpetrated the crime must have had the diabolical cunning to do it in some ordinary way that aroused no suspicion on the part of the victim, for there was no sign of any violence anywhere.

As we entered the laboratory, I noted an involuntary shudder on the part of Paula Lowe, but, as far as I knew, it was no more than might have been felt by anyone under the circumstances.

Fortescue’s body had been removed from the chair in which it had been found and lay on a couch at the other end of the room, covered merely by a sheet.  Otherwise, everything, even the armchair, was undisturbed.

Kennedy pulled back a corner of the sheet, disclosing the face, contorted and of a peculiar, purplish hue from the congested blood vessels.  He bent over and I did so, too.  There was an unmistakable odor of tobacco on him.  A moment Kennedy studied the face before us, then slowly replaced the sheet.

Miss Lowe had paused just inside the door and seemed resolutely bound not to look at anything.  Kennedy meanwhile had begun a most minute search of the table and floor of the laboratory near the spot where the armchair had been sitting.

In my effort to glean what I could from her actions and expressions I did not notice that Craig had dropped to his knees and was peering into the shadow under the laboratory table.  When at last he rose and straightened himself up, however, I saw that he was holding in the palm of his hand a half-smoked, gold-tipped cigarette, which had evidently fallen on the floor beneath the table where it had burned itself out, leaving a blackened mark on the wood.

An instant afterward he picked out from the pile of articles found in Fortescue’s pockets and lying on another table a silver cigarette case.  He snapped it open.  Fortescue’s cigarettes, of which there were perhaps a half dozen in the case, were cork-tipped.

Some one had evidently visited the inventor the night before, had apparently offered him a cigarette, for there were any number of the cork-tipped stubs lying about.  Who was it?  I caught Paula looking with fascinated gaze at the gold-tipped stub, as Kennedy carefully folded it up in a piece of paper and deposited it in his pocket.  Did she know something about the case, I wondered?

Without a word, Kennedy seemed to take in the scant furniture of the laboratory at a glance and a quick step or two brought him before a steel filing cabinet.  One drawer, which had not been closed as tightly as the rest, projected a bit.  On its face was a little typewritten card bearing the inscription:  “E-M gun.”