“Hasten slowly, William. Hasten slowly. I’ll meet you half-way. The clue in Group B was my little triumph that resulted in the discomfiture of Mademoiselle Marshall.”

“And the other two?” I persisted eagerly.

“The other two, Bill, are now three. But I haven’t developed them properly yet. There’s a missing link, somewhere, and until I get it, I’m floundering a bit. What do you make of Marshall?”

“Well,” I answered doubtfully—“I think she’s afraid of something.”

He knocked the ash out of his pipe.

“I’m curious about Marshall—she knows something she hasn’t divulged—why did she open that window? Tell me that.”

“How about Baddeley’s theory?” I put in.

“What? Acting under instructions? Open the window—then scream?” He shook his head. “Don’t think so—somehow.”

“Do you know, Bill” ... he went on, “Señorita Marshall’s face haunts me rather. I can’t get away from it.”

“Love at first sight,” I chaffed. “All good detectives do it ... think of Irene Adler.”