The matron of the nursing home received Tarling. Odette, she said, had regained her normal calm, but would require a few days' rest. She suggested she should be sent to the country.

"I hope you're not going to ask her a lot of questions, Mr. Tarling," said the matron, "because she really isn't fit to stand any further strain."

"There's only one question I'm going to ask," said Tarling grimly.

He found the girl in a prettily-furnished room, and she held out her hand to him in greeting. He stooped and kissed her, and without further ado produced the shoe from his pocket.

"Odette dear," he said gently, "is this yours?"

She looked at it and nodded.

"Why yes, where did you find it?"

"Are you sure it is yours?"

"I'm perfectly certain it's mine," she smiled. "It's an old slipper I used to wear. Why do you ask?"

"Where did you see it last?"

The girl closed her eyes and shivered.

"In mother's room," she said. "Oh, mother, mother!"

She turned her head to the cushion of the chair and wept, and Tarling soothed her.

It was some time before she was calm, but then she could give no further information.

"It was a shoe that mother liked because it fitted her. We both took the same size...."

Her voice broke again and Tarling hastened to change the conversation.

More and more he was becoming converted to Ling Chu's theory. He could not apply to that theory the facts which had come into his possession. On his way back from the nursing home to police headquarters, he reviewed the Hertford crime.

Somebody had come into the house bare-footed, with bleeding feet, and, having committed the murder, had looked about for shoes. The old slippers had been the only kind which the murderer could wear, and he or she had put them on and had gone out again, after making the circuit of the house. Why had this mysterious person tried to get into the house again, and for whom or what were they searching?

If Ling Chu was correct, obviously the murderer could not be Milburgh. If he could believe the evidence of his senses, the man with the small feet had been he who had shrieked defiance in the darkness and had hurled the vitriol at his feet. He put his views before his subordinate and found Whiteside willing to agree with him.

"But it does not follow," said Whiteside, "that the bare-footed person who was apparently in Mrs. Rider's house committed the murder. Milburgh did that right enough, don't worry! There is less doubt that he committed the Daffodil Murder."

Tarling swung round in his chair; he was sitting on the opposite side of the big table that the two men used in common.

"I think I know who committed the Daffodil Murder," he said steadily. "I have been working things out, and I have a theory which you would probably describe as fantastic."

"What is it?" asked Whiteside, but the other shook his head.

He was not for the moment prepared to reveal his theory.

Whiteside leaned back in his chair and for a moment cogitated.

"The case from the very beginning is full of contradictions," he said. "Thornton Lyne was a rich man--by-the-way, you're a rich man, now, Tarling, and I must treat you with respect."

Tarling smiled.

"Go on," he said.

"He had queer tastes--a bad poet, as is evidenced by his one slim volume of verse. He was a poseur, proof of which is to be found in his patronage of Sam Stay--who, by the way, has escaped from the lunatic asylum; I suppose you know that?"

"I know that," said Tarling. "Go on."

"Lyne falls in love wit............