The uproar out in the cave grew in volume as other members of the gang joined their comrade. There was a hasty gabble of voices.
"There was some one in the cave when I came back for the light," shouted the man who had discovered the boys. "They beat it into that tunnel. I just saw them."
"Sam, go around and watch the other side!" ordered some one sharply. "That tunnel goes out into the big cave."
The thieves were evidently unaware of the cave-in that had blocked the passage. Frank and Joe retreated beyond the first bend. They were trapped. The barricade cut off their flight, and they knew they were facing certain capture.
"The guns!" snapped Frank.
He drew his revolver from his pocket and fired into the darkness, around the corner.
There was a shout of alarm.
"Get back! Get back, Gus! They've got guns!"
Then followed a wild scrambling, as the man who had pursued them into the tunnel hustled back to safety.
Frank pressed himself against the rocky wall, in case any of the gang should enter and open fire on them. But the thieves had been frightened by his shot.