udely furnished with a heavy table and two crudely
fashioned chairs, while in the corner furthest from them two bunks had
been built, one above the other. In another corner was a compact radio
transmitting set.

At the table was seated the man with the moustache, intently studying a
notebook propped up before him. From this he made notes on a sheet of
paper, scowling at times like one engaged in a difficult task. At length
he shoved back his chair, rose to his feet, and, striding across the
little shack, carefully placed the notebook under a board on a shelf.
Luckily he was so absorbed in what he was doing that he did not even
glance toward the window where the radio boys were observing his every
motion.

But Bob now judged that they had seen enough, and he wished to run no
unnecessary risk of detection. At a signal from him they made for the
underbrush at the edge of the clearing, where they could command a view
of the door, and waited to see if the mysterious stranger would emerge.

In a few minutes the door opened and the man stepped out, stopping to
fasten it securely behind him. Then, with a quick glance about the
little clearing, he made for the path leading to the main road and in a
short time the sound of his going died away.

The boys waited a few minutes, thinking that possibly he might return
for something forgotten, but no further sound came from the path. At
length they ventured to approach the deserted cabin.

The door had been fastened with a heavy padlock, but this was not
sufficient to deter the radio boys. Searching through their pockets for
some implement with which they could undo the lock, Jimmy discovered a
stout fish-hook, and after they had ground off the barbs against a flat
stone this made an ideal tool. With it Bob probed about in the interior
of the padlock, and at length, with a sharp click, it sprung open.
Ordinarily he would not have done this, but he had every reason to
believe that he was dealing with a criminal and that he was justified in
the interest of law and order in taking steps that would prevent any
further depredations against society.

"More ways than one of killing a cat," remarked Bob, as he pushed open
the heavy door and entered the cabin. "We've got to know what's in that
notebook before we leave this place. Let's have a look."

The boys quickly brought the book from its place of concealment and
carried it to the table, where they bent eagerly over it as Bob turned