“Blood!” Kennedy exclaimed.  Then, “Look here!” The marks of the pale yellow liquid trailed into a slender trace of blood.  “It looks as if some one had cleaned a needle on it,” he muttered, “and in a hurry.”

I remembered his previous remark.  The murder had been in Tarrytown.  We had just arrived here.

“Would anyone have time to do it?” I asked.

“Whoever used the towel did so in a hurry,” he reiterated, seriously.  “It may have been some one afraid to leave any sort of clue out there at Phelps’s house.  There were too many watchers about.  It might have seemed better to have run the risk of a search.  With no sign of a wound on Miss Lamar’s person, it was pretty certain that neither Mackay nor I would attempt to frisk everyone.  It was not as though we were looking for a revolver, if she were shot, or a knife, if she had been stabbed.  And”—­he could not resist another dig at me—­“and that we should look in a washroom here for a towel was, well, an idea that wouldn’t occur to anyone but the most amateur and blundering sort of sleuth.  It’s beginner’s luck, Walter, beginner’s luck.”

I ignored the uncomplimentary part of his remarks.  “Who could have been in the washroom just before me?” I asked.

Suddenly he hurried through the waiting room to the door to Manton’s office, opening it without ceremony.  Manton was gone.  We exchanged glances.  I remembered that Werner had preceded us upstairs.  “It means Werner or Manton himself,” I whispered, so the girl just behind us would not hear.

Kennedy strode out to the hall, and to a window overlooking the court.  After a moment he pointed.  I recognized both the cars used to transport the company to the home of Emery Phelps.  There was no sign that either had just arrived, for even the chauffeurs were out of sight, perhaps melted into the crowd about the tank in the corner.

“They must have arrived immediately behind us,” Kennedy remarked.  “We wasted several valuable minutes looking at that water stuff ourselves.”

At that moment Werner’s voice rose from the reception room below.  It was probable that he would be up to rejoin us again.  I remembered that he had not been at all at ease while Kennedy questioned him in Tarrytown; that here at the studio he had been palpably anxious to remain close at our heels.  I felt a surge of suspicion within me.

“Listen, Craig,” I muttered, in low tones.  “Manton had no opportunity to steal down the hall after the girl closed the door, and—­”

“Why not!” he interrupted, contradicting me.  “We had our backs to the door while we were talking with Werner.”

“Well, anyhow, it narrows down to Manton and Werner because that is the washroom for these offices—­”

“’Sh!” Kennedy stopped me as Werner mounted the stairs.  He turned to the director with assumed nonchalance.  “How long have the other cars been here?” he asked.  “I thought we came pretty fast.”