There was a criminal in London who was watched day and night. It was no new experience to Sam Stay to find an unconcerned-looking detective strolling along behind him; but for the first time in his life the burglar was neither disconcerted nor embarrassed by these attentions.

The death of Thornton Lyne had been the most tragic blow which had ever overtaken him. And if they had arrested him he would have been indifferent. For this hang-dog criminal, with the long, melancholy face, lined and seamed and puckered so that he appeared to be an old man, had loved Thornton Lyne as he had loved nothing in his wild and barren life. Lyne to him had been some divine creature, possessed gifts and qualities which no other would have recognised in him. In Sam's eyes Lyne could have done no wrong. By Sam Stay's standard he stood for all that was beautiful in human nature.

Thornton Lyne was dead! Dead, dead, dead.

Every footfall echoed the horrible, unbelievable word. The man was incapable of feeling — every other pain was deadened in this great suffering which was his.

And who had been the cause of it all? Whose treachery had cut short this wonderful life? He ground his teeth at the thought. Odette Rider! He remembered the name. He remembered all the injuries she had done to this man, his benefactor. He remembered that long conversation which Lyne and he had had on the morning of Sam's release from prison and the plannings which had followed.

He could not know that his hero was lying, and that in his piqué and hurt vanity he was inventing grievances which had no foundation, and offences which had never been committed. He only knew that, because of the hate which lay in Thornton Lyne's heart, justifiable hate from Sam's view, the death of this great man had been encompassed.

He walked aimlessly westward, unconscious of and uncaring for his shadower, and had reached the end of Piccadilly when somebody took him gently by the arm. He turned, and as he recognised an acquaintance, his thick lips went back in an ugly snarl.

"It's all right, Sam," said the plain-clothes policeman with a grin. "There's no trouble coming to you. I just want to ask you a few questions."

"You fellows have been asking questions day and night since — since that happened," growled Sam.

Nevertheless, he permitted himself to be mollified and led to a seat in the Park.

"Now, I'm putting it to you straight, Sam," said the policeman. "We've got nothing against you at the Yard, but we think you might be able to help us. You knew Mr. Lyne; he was very decent to you."

"Here, shut up," said Sam savagely. "I don't want to talk about it. I don't want to think about it! D'ye hear? He was the grandest fellow that ever was, was Mr. Lyne, God bless him! Oh, my God! My God!" he wailed, and to the detective's surprise this hardened criminal buried his face in his hands.

"That's all right, Sam. I know he was a nice fellow. Had he any enemies — he might have talked to a chap like you where he wouldn't have talked to his friends."

Sam, red-eyed, looked up suspiciously.

"Am I going to get into any trouble for talking?" he said.

"None at all, Sam," said the policeman quickly. "Now, you be a good lad and do all you can to help us, and maybe, if you ever get into trouble, we'll put one in for you. Do you see? Did anybody hate him?"

Sam nodded.

"Was it a woman?" asked the detective with studied indifference.

"It was," replied the other with an oath. "Damn her, it was! He treated her well, did Mr. Lyne. She was broke, half-starving; he took her out of the gutter and put her into a good place, and she went about making accusations against him!"

He poured forth a stream of the foulest abuse which the policeman had ever heard.

"That's the kind of girl she was, Slade," he went on, addressing the detective, as criminals will, familiarly by their surnames. "She ain't fit to walk the earth ——”

His voice broke.

"Might I ask her name?" demanded Slade.

Again Sam looked suspiciously around.

"Look here," he said, "leave me to deal with her. I'll settle with her, and don't you worry!"

"That would only get you into trouble, Sam," mused Slade. "Just give us her name. Did it begin with an 'R'?"

"How do I know?" growled the criminal. "I can't spell. Her name was Odette."

"Rider?" said the other eagerly.

"That's her. She used to be cashier in Lyne's Store."

"Now, just quieten yourself down and tell me all Lyne told you about her, will you, my lad?"

Sam Stay stared at him, and then a slow look of cunning passed over his face.

"If it was her!" he breathed. "If I could only put her away for it!"

Nothing better illustrated the mentality of this man than the fact that the thought of "shopping" the girl had not occurred to him before. That was the idea, a splendid idea! Again his lips curled back, and he eyed the detective with a queer little smile.

"All right, sir," he said. "I'll tell the head-split. I'm not going to tell you."

"That's as it ought to be, Sam," said the detective genially. "You can tell Mr. Tarling or Mr. Whiteside and they'll make it worth your while."

The detective called a cab and together they drove, not to Scotland Yard, but to Tarling's little office in Bond Street. It was here that the man from Shanghai had established his detective agency, and here he waited with the phlegmatic Whiteside for the return of the detective he had sent to withdraw Sam Stay from his shadower.

The man shuffled into the room, looked resentfully from one to the other, nodded to both, and declined the chair which was pushed forward for him. His head was throbbing in an unaccountable way, as it had never throbbed before. There were curious buzzes and noises in his ears. It was strange that he had not noticed this until he came into the quiet room, to meet the grave eyes of a hard-faced man, whom he did not remember having seen before.

"Now, Stay," said Whiteside, whom at least the criminal recognised, "we want to hear what you know about this murder."

Stay pressed his lips together and made no reply.

"Sit down," said Tarling, and this time the man obeyed. "Now, my lad," Tarling went on — and when he was in a persuasive mood his voice was silky — "they tell me that you were a friend of Mr. Lyne's."

Sam nodded.

"He was good to you, was he not?"

"Good?" The man drew a deep breath. "I'd have given my heart and soul to save him from a minute's pain, I would, sir! I'm telling you straight, and may I be struck dead if I'm lying! He was an angel on earth — my God, if ever I lay me hands on that woman, I'll strangle her. I'll put her out! I'll not leave her till she's torn to rags!"

His voice rose, specks of foam stood on his lips his whole face seemed transfigured in an ecstasy of hate.

"She's been robbing him and robbing him for years," he shouted. "He looked after her and protected her, and she went and told lies about him, she did. She trapped him!"

His voice rose to a scream, and he made a move forward towards the desk, both fists clenched till the knuckles showed white. Tarling sprang up, for he recognised the signs. Before another word could be spoken, the man collapsed in a heap on the floor, and lay like one dead.

Tarling was round the table in an instant, turned the unconscious man on his back, and, lifting one eyelid, examined the pupil.

"Epilepsy or something worse," he said. "This thing has been preying on the poor devil's mind — 'phone an ambulance, Whiteside, will you?"

"Shall I give him some water?"

Tarling shook his head.

"He won't recover for hours, if he recovers at all," he said. "If Sam Stay knows anything to the detriment of Odette Rider, he is likely to carry his knowledge to the grave."

And in his heart of hearts J. O. Tarling felt a little sense of satisfaction that the mouth of this man was closed.