"They probably had some secret hiding place which we didn't find," declared Mr. Golden.
"I guess that's about the size of it. Here, Bill, I guess you and Fred are the strongest, you two get up on that ladder and see if you can make any impression on that door. I wonder how, in the name of all that's funny, they have fastened it, for I didn't see any lock on it."
The two officers did as ordered, but in spite of their most strenuous efforts, they could make no impression on it. They did, however, make a most decided impression on the ladder, for suddenly it broke near the middle, and the two came tumbling down in a heap. Fortunately, they were not hurt by the fall and laughed as they picked themselves up.
"Well, we're in a pretty fix, sure enough," declared Captain Long. "I should have left one of you on guard, but I never thought of those fellows being in hiding there after the way we searched the place. It's a good thing I left word at the station where we were going, but the rest of the force will sure have the laugh on us."
"Say, do you smell anything?" suddenly asked Bob.
"Seem's though I do," replied two of the officers sniffing.
No one spoke for a moment and then Captain Long said:
"My God, men, that's coal gas and it's getting stronger every minute. Those devils have turned it in here somehow. Quick," he almost shouted, "we've got to get out of here at once or we'll all be dead men in less than ten minutes."
By this time the odor of the gas was very strong and was rapidly getting stronger. Several of the officers were equipped with electric torches, and using them, they made a hurried search of the walls to see if by chance there was any opening which they had overlooked before, but nothing of the kind could they find.