Tarling went back to his lodgings that afternoon, a puzzled and baffled man. Ling Chu, his impassive Chinese servant, had observed those symptoms of perplexity before, but now there was something new in his master's demeanour--a kind of curt irritation, an anxiety which in the Hunter of Men had not been observed before.

The Chinaman went silently about the business of preparing his chief's tea and made no reference to the tragedy or to any of its details. He had set the table by the side of the bed, and was gliding from the room in that cat-like way of his when Tarling stopped him.

"Ling Chu," he said, speaking in the vernacular, "you remember in Shanghai when the 'Cheerful Hearts' committed a crime, how they used to leave behind their _hong_?"

"Yes, master, I remember it very well," said Ling Chu calmly. "They were certain words on red paper, and afterwards you could buy them from the shops, because people desired to have these signs to show to their friends."

"Many people carried these things," said Tarling slowly, "and the sign of the 'Cheerful Hearts' was found in the pocket of the murdered man."

Ling Chu met the other's eyes with imperturbable calmness.

"Master," he said, "may not the white-faced man who is now dead have brought such a thing from Shanghai? He was a tourist, and tourists buy these foolish souvenirs."

Tarling nodded again.

"That is possible," he said. "I have already thought that such might have been the case. Yet, why should he have this sign of the 'Cheerful Hearts' in his pocket on the night he was murdered?"

"Master," said the Chinaman, "why should he have been murdered?"

Tarling's lips curled in a half smile.

"By which I suppose you mean that one question is as difficult to answer as the other," he said. "All right, Ling Chu, that will do."

His principal anxiety for the moment was not this, or any other clue which had been offered, but the discovery of Odette Rider's present hiding-place. Again and again he turned the problem over in his mind. At every point he was baffled by the wild improbability of the facts that he had discovered. Why should Odette Rider be content to accept a servile position in Lyne's Stores when her mother was living in luxury at Hertford? Who was her father--that mysterious father who appeared and disappeared at Hertford, and what part did he play in the crime? And if she was innocent, why had she disappeared so completely and in circumstances so suspicious? And what did Sam Stay know? The man's hatred of the girl was uncanny. At the mention of her name a veritable fountain of venom had bubbled up, and Tarling had sensed the abysmal depths of this man's hate and something of his boundless love for the dead man.

He turned impatiently on the couch and reached out his hand for his tea, when there came a soft tap at the door and Ling Chu slipped into the room.

"The Bright Man is here," he said, and in these words announced Whiteside, who brought into the room something of his alert, fresh personality which had earned him the pseudonym which Ling Chu had affixed.

"Well, Mr. Tarling," said the Inspector, taking out a little notebook, "I'm afraid I haven't done very much in the way of discovering the movements of Miss Rider, but so far as I can find out by inquiries made at Charing Cross booking office, several young ladies unattended have left for the Continent in the past few days."

"You cannot identify any of these with Miss Rider?" asked Tarling in a tone of disappointment.

The detective shook his head. Despite his apparent unsuccess, he had............