“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 voice like a fog-horn.

Twenty cups of tea, coffee and cocoa, too hot for speedy assimilation, were spilled upon the floor.