"What do you mean?" asked Tarling.

"I'll swear to that thumb-print," replied Whiteside. "It's identical with
the blood mark which was left on Miss Rider's bureau on the night of the
murder!"

"Are you sure?"

"Absolutely," said Whiteside, speaking quickly. "Do you see that whorl?
Look at those lineations! They're the same. I have the original
photograph in my pocket somewhere." He searched his pocket-book and
brought out a photograph of a thumb-print considerably enlarged.

"Compare them!" cried Whiteside in triumph. "Line for line, ridge for
ridge, and furrow for furrow, it is Milburgh's thumb-print and Milburgh
is my man!"

He took up his coat and slipped it on.

"Where are you going?"

"Back to London," said Whiteside grimly, "to secure a warrant for the
arrest of George Milburgh, the man who killed Thornton Lyne, the man who
murdered his wife--the blackest villain at large in the world to-day!"

CHAPTER XXIX

THE THEORY OF LING CHU

Upon this scene came Ling Chu, imperturbable, expressionless, bringing
with him his own atmosphere of mystery.

"Well," said Tarling, "what have you discovered?" and even Whiteside
checked his enthusiasm to listen.

"Two people came up the stairs last night," said Ling Chu, "also the
master." He looked at Tarling, and the latter nodded. "Your feet are
clear," he said; "also the feet of the small-piece woman; also the naked
feet."

"The naked feet?" said Tarling, and Ling Chu assented.

"What was the naked foot--man or woman?" asked Whiteside.

"It may have been man or woman," replied the Chinaman, "but the feet were
cut and were bleeding. There is mark of blood on the gravel outside."

"Nonsense!" said Whiteside sharply.

"Let him go on," warned Tarling.

"A woman came in and went out----" continued Ling Chu.

"That was Miss Rider," said Tarling.

"Then a woman and a man came; then the bare-footed one came, because the
blood is over the first women's footmarks."

"How do you know which was the first woman and which was the second?"
asked Whiteside, interested in spite of himself.

"The first woman's foot was wet," said Ling Chu.

"But there had been no rain," said the detective in triumph.

"She was standing on the grass," said Ling Chu, and Tarling nodded his
head, remembering that the girl had stood on the grass in the shadow of
the bushes, watching his adventure with Milburgh.

"But there is one thing I do not understand master," said Ling Chu