Again the ranger paused and studied Charley’s face keenly.  Evidently the wide-set eyes, with their indication of intelligence, the strong nose and good chin, and especially Charley’s straight mouth with its thin lips, reassured him.  “My boy,” he said kindly, “I don’t want to alarm you unnecessarily, but be careful of that man.  He’s up to something, or he wouldn’t be in this forest; but what it can be, I’ve not the remotest idea.  The only thing I can think of that would bring him here is the virgin timber.  He’s been mixed up in several crooked lumber deals.  He wouldn’t hesitate for an instant to steal timber or to set the forest afire.  And it’s my personal belief that he wouldn’t stop at”—­he paused and studied Charley’s face again—­“at murder.”

The two boys were sober.  For a moment they looked at the ranger in silence.  Then, “What had I better do?” asked Charley.

“Keep out of Collins’ road,” answered Mr. Morton instantly.  “If you can get track of him, watch him; but don’t let him see you or know he is watched.”

Again the ranger paused to ponder the matter.  “It isn’t a square deal to let you kids go up against that old crook,” he said suddenly.  “Come on.  We’ll see if we can find him.  And if we do, I know how to deal with him.”

The ranger strode forward at a terrific pace.  The two boys had almost to run to keep up with him.  Over his face came a grim expression that boded no good for Bill Collins.  On and on he went, saying never a word.  Evidently he was revolving the situation in his own mind.  Not until they reached the brook did he utter a syllable.  Then he said, “Show me exactly where you boys were and where the two men came out of the bushes.”

Charley pointed out the respective positions.  Mr. Morton searched the bushes but found nothing enlightening.

“Which way did they go after they left you?” he asked.

Lew pointed out the route they had taken.  Along the margin of the brook both men had left clear footprints.  Mr. Morton sank to his knees and the three studied these prints closely.  Then, “Come on,” he said, rising.  “We’ll see if we can trail them.”

Lew led the way to the point at which they had last seen the men.  The disturbed condition of the leaves showed plainly that some one had passed.  Very slowly and painstakingly the ranger followed the trail.  In many places the forest mold still retained the imprint of a foot distinctly.  So they followed the trail for several rods.  Then they were unable to find any more footprints, nor did the leaves appear disturbed in any way.

“They’ve turned off to one side or the other,” said the ranger, when he was sure they had overrun the trail.  “Let’s see if we can find which way they went.”

The three investigators turned and spread out, advancing a foot at a time, and examined the ground minutely.  Not a leaf nor a stick, nor yet the bushes or tree trunks escaped observation.  At last Charley gave a little cry.  He had found a footprint that corresponded exactly with one they had studied by the brook.  A little farther on a second imprint was visible, and the leaves again had the appearance of having been disturbed.  For some distance they continued to search for and to find footprints and other unmistakable signs of the passage of the two men.