h when a dock light, shining out across the river, outlined the boat
yellowly.

"He's got a passenger!" said Coombes amazedly.

Inspector White, who was in charge of the cutter, rested his arm on
Coombes' shoulder and stared across the moving tide.

"I can see no one," he replied. "You're over anxious,
Detective-Sergeant--and I can understand it!"

Coombes smiled heroically.

"I may be over anxious, Inspector," he replied, "but if I lost Sin Sin
Wa, the River Police had never even heard of him till the C.I.D. put 'em
wise."

"H'm!" muttered the Inspector. "D'you suggest we board him?"

"No," said Coombes, "let him land, but don't trouble to hide any more.
Show him we're in pursuit."

No longer drifting with the outgoing tide, George Martin had now boldly
taken to the oars. The River Police boat close in his wake, he headed
for the blunt promontory of the Isle of Dogs. The grim pursuit went on
until:

"I bet I know where he's for," said Coombes.

"So do I," declared Inspector White; "Dougal's!"

Their anticipations were realized. To the wooden stairs which served as
a water-gate for the establishment on the Isle of Dogs, George Martin
ran in openly; the police boat followed, and:

"You were right!" cried the Inspector, "he has somebody with him!"

A furtive figure, bearing a burden upon its shoulder, moved up the slope
and disappeared. A moment later the police were leaping ashore. George
deserted his boat and went running heavily after his passenger.

"After them!" cried Coombes. "That's Sin Sin Wa!"

Around the mazey, rubbish-strewn paths the pursuit went hotly. In sight
of Dougal's Coombes saw the swing door open and a silhouette--that of a
man who carried a bag on his shoulder--pass in. George Martin followed,
but the Scotland Yard man had his hand upon his shoulder.

"Police!" he said sharply. "Who's your friend?"

George turned, red and truculent, with clenched fists.

"Mind your own bloody business!" he roared.

"Mind yours, my lad!" retorted Coombes warningly. "You're no Thames
waterman. Who's your friend?"

"Wotcher mean?" shouted George. "You're up the pole or canned you are!"

"Grab him!" said Coombes, and he kicked open the door and entered the
saloon, followed by Inspector White and the boat's crew.

As they appeared, the Inspector conspicuous in his uniform, backed by
the group of River Police, one of whom grasped George Martin by his coat
collar:

"Splits!" bellowed Dougal in a