ABOUT TEN MINUTES AFTER Alleyn got back to his own flat that night, Nigel's call came through.

"Got you at last," he said.

"Did you ring up at Surbonadier's flat about twenty minutes after you left it?" asked Alleyn.

"Yes. How did you know?"

"I heard you."

"Well, why the deuce didn't you answer?"

"I was under the bed."

"What? This telephone's very bad."

"Never mind. What's the matter?"

"I've been to see Felix. He asked me to. You were right."

"Well, not over the telephone. Come to the Yard at nine to -mor row."

"All right," said Nigel. "Good night."

"Flights of angels sing thee to thy rest," said Alleyn wearily, and went to bed.

Next morning Nigel arrived at Scotland Yard with his copy and his messenger boy.

"This is becoming a habit," said Alleyn. He censored the story and the remains were dispatched to Fleet Street.

"Now," said Nigel, "listen!"

He told his story of Gardener's confession, and of the anonymous letter, which he produced. Alleyn listened attentively and examined the paper very carefully.

"I'm glad he decided to tell you this," he said. "Do you think he would repeat it and sign a statement to the same effect?"

"I think so. As far as I could gather, after he had got over the first shock of having killed Surbonadier, he began to think you'd suspect him of malice aforethought. Later on, after I'd heard Miss Vaughan ask him not to repeat whatever it was, he felt it was she who was in danger and that he must tell you everything he knew that would be likely to draw your suspicions away from her. He realises that what he has said definitely implicates Saint, and may implicate himself. He's not at all sure Saint did it. He's inclined to think it's suicide."

"So is our Mr. Saint—very much inclined," said Alleyn grimly. He pressed the bell on his desk.

"Ask Inspector Fox to come in," he said to the constable who answered it.

He examined the paper again in silence, until the inspector arrived.

"Glad tidings, Fox," said Alleyn. "Our little murderer has come all over literary. He's writing letters. One begins to see a glim."

"Does one?" asked Nigel.

"But certainly. Fox, this letter arrived at Mr. Gardener's flat, by district messenger, at about eight-thirty last night. There's the envelope. The district messenger offices will have to be combed out. Have it tested for prints. You'll find Gardener and an 'unknown.' I've a pretty good idea who the unknown is."

"May I ask who?" Fox ventured eagerly.

"A man who, in all honesty, I think I may say we have never, in the course of our speculation, suspected of this crime; a man who, by his apparent eagerness to help the police, by his frequent suggestions, as well as by his singular charm of manner, has succeeded so far in escaping even our casual attention. And that man's name is—"