"I can't understand what has happened to Ling Chu. He should be back by now," said Tarling. It was half-past one in the morning, and a telephone inquiry to Scotland Yard had produced no information. "It is possible, of course," Tarling went on, "that Stay took the cab on to Hertford. The man has developed into a dangerous lunatic." "All criminals are more or less mad," said the philosophical Whiteside. "I wonder what turned this fellow's brain." "Love!" said Tarling. The other looked at him in surprise. "Love?" he repeated incredulously, and Tarling: nodded. "Undoubtedly Sam Stay adored Lyne. It was the shock of his death which drove him mad." Whiteside drummed his fingers on the table, thoughtfully. "What do you think of Milburgh's story?" he asked, and Tarling shrugged his shoulders. "It is most difficult to form a judgment," he said. "The man spoke as though he were telling the truth, and something within me convinces me that he was not lying. And yet the whole thing is incredible." "Of course, Milburgh has had time to make up a pretty good story," warned Whiteside. "He is a fairly shrewd man, this Milburgh, and it was hardly likely that he would tell us a yarn which was beyond the range of belief." "That is true," agreed the other, "nevertheless, I am satisfied he told almost the whole of the truth." "Then, who killed Thornton Lyne?" Tarling rose with a gesture of despair. "You are apparently as far from the solution of that mystery as I am, and yet I have formed a theory which may sound fantastic----" There was a light step upon the stair and Tarling crossed the room and opened the door. Ling Chu came in, his calm, inscrutable self, and but for the fact that his forehead and his right hand were heavily bandaged, carrying no evidence of his tragic experience. "Hello, Ling Chu," said Tarling in English, "you're hurt?" "Not badly," said Ling Chu. "Will the master be good enough to give me a cigarette? I lost all mine in the struggle." "Where is Sam Stay?" Ling Chu lit the cigarette before he answered, blew out the match and placed it carefully in the ash-tray on the centre of the table. "The man is sleeping on the Terrace of Night," said Ling Chu simply. "Dead?" said the startled Tarling. The Chinaman nodded. "Did you kill him?" Again Ling Chu paused and puffed a cloud of cigarette smoke into the air. "He was dying for many days, so the doctor at the big hospital told me. I hit his head once or twice, but not very hard. He cut me a little with a knife, but it was nothing." "Sam Stay is dead, eh?" said Tarling thoughtfully. "Well, that removes a source of danger to Miss Rider, Ling Chu." The Chinaman smiled. "It removes many things, master, because before this man died, his head became good." "You mean he was sane?" "He was sane, master," said Ling Chu, "and he wished to speak to paper. So the big doctor at the hospital sent for a judge, or one who sits in judgment." "A magistrate?"