The three ran forward, paying little heed until they reached the edge of the ravine.  Here the beaten trail swerved sharply to the right.  Fifty feet beyond, the marks of horses’ hoofs appeared on the sloping bank, and Hamlin sprang down to where the marks disappeared around the edge of a large bowlder.  His hand on the stone, he stopped suddenly with quick indrawing of breath, staring down at a motionless figure lying almost at his feet.  The man, roughly dressed, lay on his face, a bullet wound showing above one ear, the back of his neck caked with blood.  The Sergeant, mastering his first sense of horror, turned him over and gazed upon the ghastly face of Major McDonald.

“My God, they’ve murdered him here!” he exclaimed.  “Shot him down from behind.  Look, men.  No; stand back, and don’t muss up the tracks.  There are foot-prints here—­Indians, by heaven!  Three of them Indians!”

“Some plainsmen wear moccasins.”

“They don’t walk that way—­toes in; and see this hair in McDonald’s fingers—­that’s Indian, sure.  Here is where a horse fell, and slid down the bank.  Is n’t that a bit of broken feather caught in the bush, Carroll?  Bring it over here.”

The three bent over the object.

“Well, what do you say?  You men are both plainsmen.”

“Cheyenne,” returned Carroll promptly.  “But what the hell are they doing here?”

Hamlin shook his head.

“It will require more than guessing to determine that,” he said sternly.  “And there is only one way to find out.  That fellow was a Cheyenne all right, and there were three of them and two whites in the party—­see here; the prints of five horses ridden, and one animal led.  That will be the one McDonald had.  They went straight up the opposite bank of the ravine.  If they leave a trail like that we can ride after them full speed.”

Carroll had been bending over the dead officer and now glanced up.

“There’s sand just below, Sergeant,” he said.  “That’s why they are so darn reckless here.”

“Of course; they’ll hide in the dunes, and the sooner we ’re after them the better.  Wade, you remain with the body; Carroll and I will return to the fort and report.  We ’ll have to have more men—­Wasson if I can get him—­and equipment for a hard ride.  Come on, Jack.”

They waded the river, and ran through the town, shouting their discovery to the marshal and his posse as they passed.  Twenty minutes later Hamlin stood before the Colonel, hastily telling the story.  The latter listened intently, gripping the arms of his chair.

“Shot from behind, hey?” he ejaculated, “and his clothing stolen.  Looks like a carefully planned affair, Sergeant; sending that fellow through to Ripley was expected to throw us off the track.  That ’s why they were so careless covering their trail; expected to have several days’ start.  It is my notion they never intended to kill him; had a row of some kind, or else Mac tried to get away.  Any trace of the girl?”