“Shirley is missing,” observed the district attorney, in an undertone.

Kennedy faced me.  “Give the bag to Mackay, Walter.  While he keeps an eye on the people up here we’ll pay a visit to Shirley’s dressing room, and after that go down to the basement again.  I can’t account for it—­intuition, perhaps—­but I’m sure something’s wrong.”

The heavy man’s dressing room, pointed out to us by some employee passing through the hall, was empty.  I led the way into Marilyn’s quarters, but again no one was about.  In each case Kennedy made a quick visual search for the towel, without result.  We did not dare linger and run the risk of giving away our trick; then, too, Kennedy was nervously anxious to look through the basement once more.

“I don’t understand your suspicion of the state of affairs in the film vaults,” I confessed.

“Why should Jack Gordon, the leading man, be down there?” he countered.

“That—­that really is a cause for suspicion, isn’t it.”

“Now, Walter, think a bit!” We were crossing the yard, and so not apt to be overheard.  “Granting that Gordon actually had been down there, why should the fact concern us?  Manton explained that no negative or positive can be given out except upon order.  There is nothing down there but film and so no other errand to bring the leading man to the vault except to get some scenes or pieces showing his own work, and that isn’t likely.”

“Unless,” I interrupted, “Gordon is the guilty man and wanted to get the snake film before we did.”

“How could that be?  When we asked Manton about the Doctor Nagoya subject we went right down with him and procured it.  I doubt anyone could have overheard us as we talked about it, in any case.”

“Remember, Craig, we went to the locker first and it was some little time before that fellow came out to unlock it and give us the key.  And when you questioned Manton we were passing right by all of them.  Any one could have heard the mention of the snake film.”

Kennedy frowned.  “I believe you’re right, Walter.  Or it is possible that the guilty person believed that the scenes taken out at Tarrytown, or those taken when Werner died, revealed something and so would have to be stolen or destroyed, and that they were kept in the vault.  It is even possible”—­a gleam came into Kennedy’s eyes—­“it is even possible that the mind smart enough to reason out the damaging nature of the chemical analyses I was making, and clever enough to utilize an explosive bullet in an effort to destroy the fruits of my work, would also have the foresight to anticipate me and to realize that I might guess the existence of a film showing snakes and suggesting the use of venom.”

“It’s damning to Gordon, all right,” I said.

“On the contrary, Walter.”  Kennedy lowered his voice as we entered the building across the quadrangle and descended stairs leading directly into the basement.  “We have mentioned over and over again the cleverness of our unknown criminal.  That man, or woman, never would drop a cigarette case with his or her initials and leave without it, nor smoke a cigarette in a place he, or she, was not supposed to be.”