expect to find his purse. Robbery and murder--murder for the sake of
robbery--that's what it is, Mr. Viner! Westbourne Grove way, you say this
fellow went? And five minutes' start!"

"Is it any good getting a doctor?" asked Viner.

"A thousand doctors'll do him no good," replied the policeman grimly.
"But--there's Dr. Cortelyon somewhere about here--number seven in the
terrace. One of these back doors is his. We might call him."

He turned the light of his lantern on the line of doors in the
right-hand wall, and finding the number he wanted, pulled the bell. As
its tinkle sounded somewhere up the yard behind, he thrust his whistle
into Viner's hand.

"Mr. Viner," he said, "go up to the end of the passage and blow on that
as loud as you can, three times. I'll stand by here till you come back.
If you don't hear or see any of our people coming from either direction,
blow again."

Viner heard steps coming down the yard behind the door as he walked away.
And he heard more steps, hurrying steps, as he reached the end of the
passage. He turned it to find an inspector and a sergeant approaching
from one part of the terrace, a constable from another.

"You're wanted down here," said Viner as they all converged on him.
"There's been murder! One of your men's there--he gave me this whistle to
summon further help. This way!"

The police followed him in silence down the passage. Another figure had