"That'll do very well for a theory," replied George.
"I'll go you a plate of cookies," argued Sandy, "that Will is right, and that this third boy is hanging around taking messages from the two boys in the mine and also to the two boys in the mine."
"Didn't I say it was all right for a theory?" chuckled George.
"Now, the point is this," Will continued. "What are those boys in the mine for? What do they want there? Why didn't they answer our Boy Scout challenge when we replied to their call of the pack?"
"If you don't ask so many questions, you won't get so many negative answers," Sandy advised. "We're here to find the boys, and I don't see that it makes any difference to us what they're in there for."
"But we've found the boys now," contended Tommy. "We haven't got our hands on them yet, of course, but we know they're in there, and we know it's only a question of time when we get hold of them."
"Well," Will insisted, "I'm going to find a motive before I quit the case. I'm going to know who sent those boys here, and all about it, before I make any report to Mr. Horton."
"Go as far as you like," laughed Tommy. "My bump of curiosity is growing half an inch a day, and will continue to spread out until I find out exactly what those boys are doing burrowing in a deserted mine."
"Now, we'll get back to the point we started from," Will explained. "This boy who is undoubtedly doing duty outside the mine in the interests of the persons who sent the two boys in, furnishes the clue to the whole situation! When we find him, and find out what he's up to, and trace any communications he may make back to their original source, we'll have the whole case tied up tight!"
"That's right!" declared Tommy. "We'll have the case tied up tight if we succeed in getting hold of this third boy."