I shook my head, but Kennedy continued.
"As a matter of fact, the use of that drug is not less clever than the use of the venom or the toxin; it is more so. Stop and think a minute! The snake venom was employed in the case of Miss Lamar's death because it offered about the least possible chance of leaving telltale clues behind. The snake poison could be inflicted with a tiny scratch, and in such a way that an outcry from the girl would never be noticed. Nothing but my pocket lens caught the scratch; only the great care I used in my examination put us on the trail at all.
"Now remember how Werner met his death. The toxin gave every symptom of food poisoning. Except that we discovered the broken stem of the wineglass we would never have been able to prove the tragedy anything but accident. Very possibly we have Shirley to thank for the fact that our one clue there was not removed or destroyed.
"In both cases the selection of the poison was suited to the conditions. Therefore, if an attempt was made to kill Shirley—and of the fact I am sure—we might expect that the agent likewise would be one least apt to create suspicion. There are no portieres, no opportunity for the use of another venom; and besides, that has lost its novelty, and so its value. Similarly there is no use of food or wine in the scene, precluding something else along the toxin order.
"Our unknown realizes that the safest place to commit murder is where there is a crowd. He has followed that principle consistently. In the case of the heavy man, who has a bit of business before the camera where he drinks the contents of a little bottle, the very cleverest thing is to use belladonna, because Shirley has employed it for his eyes, and because"—maliciously, almost—"it leads immediately to the hypothesis of suicide."
"Ye gods, Craig!" A sudden thought struck me and rather terrified me. "Do you suppose Enid Faye suggested the use of the drug to Shirley as part of the scheme to kill him? Is she—"
"I prefer," Kennedy interrupted—"I prefer to suppose that the guilty person overheard her, or perhaps saw him buy it or learned in some other way that he was going to use it."
Completely taken up with this new line of thought, I failed to question Kennedy further, and it was just as well because most of the people were on their way down to the projection room, not only those we wished present, but practically everyone of sufficient importance about the studio to feel that he could intrude.
Kennedy turned to Mackay, who had taken no part in our discussion, although an interested listener. "You have the bag and all the evidence?"
"Yes!" Mackay picked it up. "Watkins, the camera man, watched it for me while Jameson and I went after that drug."