At that moment there came the sudden crack and roar of an explosion. Its blast flung them both forward on their knees. As they picked themselves up they looked round to find that the engine-house was now a smoking ruin. Shouts and screams were coming from it. Troops and police were running to the assistance of their wounded comrades. For a few minutes everything was confusion.

As the smoke above the wrecked building cleared Barney suddenly shouted, 'Look! Look! There he is. The explosion has brought the murdering swine out to see the results of his handiwork.'

Following Barney's pointing ringer, C.B. saw that a figure had emerged from the cave and was now standing on the edge of the broad ledge, looking down through a pair of glasses at the scene of havoc. He, too, had no doubt that it was Lothar.

Richter staggered up to them, his face blackened, his eyebrows singed and his uniform torn.

'What happened?' Verney asked him.

The American was still panting. 'That devil had booby-trapped both the cage and the engine. I chanced to be looking towards the winding gear as a corporal pushed over the lever. Both bombs went off simultaneously. The Brigadier and Jodelweiss were both in the cage. With them and in the freight compartment they had several sappers; bomb experts. All of them are to hell and gone. So are six or eight fellers who were standing round the engine. I was lucky. I couldn't get a place in the cage but I was standing alongside it by the opening. So I was blown clear.'

As he finished speaking Fratelli limped up to them. He had been outside the building but near it, and a flying length of wooden rafter had caught him a nasty blow on his left leg. Otto had escaped altogether, as he had been well away from the engine-house and, already certain in his own mind that Lothar was still in the cave, was staring up at it.

Within a few minutes the last of the wounded had been rescued from the smouldering debris, and a tall, thin Major came up to them. The greater part of the troops were his own men and, now that the Brigadier had been killed, he was the senior officer present. After expressing his fury that the police should have allowed them to walk into such a trap, he demanded to know the object of the operation.

In a low voice Fratelli told him, upon which he promptly declared his intention of having his tanks train their guns on the cave and shell it to blazes. The others swiftly implored him not to, as they feared that the concussion of the bursting shells might set off the H bomb war-head that they believed to be at the far end of the tunnel. It was Verney who said,