"There's a new caretaker on a tier of barges just above Tower Bridge," whispered Wrington tensely. "We'll try there first. Keep your voice low if you want to speak, sir. Sound travels a long way on the water. Ah, there it is." Foyle had got good eyesight, but he could make out nothing but a smudge where Wrington pointed--a smudge emphasised by a tiny point of twinkling light. The two motor-boats slowed down and approached, as it were, on tiptoe one on either side of the vessel. As they came nearer a barge took shape at the head of a long string. "Stop her," ordered Wrington. "Now, sir, will you board her with me? Get ready." As they lurched against the sides of the craft the two leapt aboard. Green and Jones had come up from the other side. The superintendent gave a whispered order, and the other three ranged themselves around a small deck cabin, while he thrust open the door and entered. It was quite dark within, and a smell of stale tobacco smoke met his nostrils. He stood still and lit a match, holding himself in readiness for anything. A figure was dozing in a chair at the other side of the cabin. Foyle crossed stealthily and quietly encircled the man around the waist, pressing his arms to his side with all his strength. The man, suddenly awakened, struggled vigorously. "Keep still," ordered Foyle, doggedly maintaining his hold. "Hi, Green, Wrington! Give me a hand here, will you?" CHAPTER XXXIV Powerful as he was and with his prisoner at a disadvantage, Foyle found it all he could do to maintain his hold until his companions broke through to his help. Even then it was no easy task, and the fight raged over the tiny cabin with the police hanging on to their prisoner like dogs to a wounded bear. No one spoke a word; there was only the quick panting of struggling men, the shuffling of their footsteps, and now and again a sharp crash as some piece of furniture overturned. Their very numbers handicapped the police in that confined space. Hands sometimes tore at Foyle, sometimes at the prisoner. The superintendent hung on with the tenacity of a bulldog, until a sudden lurch against the side brought his head sharply in contact with the boarding. Half dazed, he involuntarily relaxed his grip. The prisoner tore himself away and struck out viciously. A man fell heavily. For the fraction of a second a shadowy figure was indistinctly outlined in the doorway. Almost simultaneously Foyle, Green, and Wrington flung themselves in pursuit. They were too late. A soft splash told that the man had taken the only possible avenue of escape. "Look lively with those boats. He's gone overboard," yelled Wrington. "Light up and get close in to the bank."