The motive underlying the attack upon the constable was understandable. The young policeman had traveled across the range on official business, and his slayer no doubt had reason to put him out of the way. But the man who shot Graves, in his turn was shot and killed. And Mudgett also! It was not so easy to fathom the motive of this double affair in the cabin.
Dexter recalled every word spoken by the mysterious voice, before the gun reports sounded behind the closed door. The woman had mentioned the prisoners under arrest, and expressed the fear that they might be forced to talk. What could they talk about—what dangerous secret did they know? It must be something dreadful, if such a desperate method were needed to enforce their silence.
From the scanty facts in his possession the corporal tried to pick out some logical thread of connection between the people thus far enmeshed in the threefold tragedy of the wilderness: Mudgett, the stranger in the upper bunk, the woman from nowhere. Besides these there was the trapper, Stark, who, Mudgett declared, had built himself a winter shack farther up the valley. 'Phonse Doucet, the assailant of the Crooked Forks store keeper, had escaped somewhere on this side of the mountains. So there were five, at least, who had suddenly pushed across into this lonesome, isolated territory where even the marks of squaw-hatchets were seldom found.
Nor had Dexter forgotten the face of the man in the Bertillon photograph, which Constable Graves carried in his pocket. And for some reason the name of "Pink" Crill stuck insistently in his mind. Was this outlander also sojourning in the wilderness? And if so, was he in any way involved in the affairs of the others? There was no saying. Yet the corporal could not escape the feeling that he had touched the sinister web of some large criminal business—of plot and counterplot—that entangled the members of some unidentified outlaw band. What hope of profit might draw traffickers in organized crime to such infertile, out-of-the-way fields, he was unable to guess. He only knew that the country had been suddenly invaded by a mysterious and dangerous company of intruders.
His glance returned grimly to the silent figures in the bunks. No doubt these two held the secret, of which he himself had failed to find the key. But he could scarcely believe that murder had been committed just to prevent their telling what they might know. If this were the only motive, why was not the policeman shot instead of his prisoners? Dexter had not dreamed of the presence of a third person in the cabin, and the woman might have left the door unbarred and ambushed him with perfect safety as he entered.
He shook his head grimly. There must have been other reasons for the wanton shooting. Vengeance? The voice had said something about being betrayed. Had Mudgett or his companion sent the word that summoned Constable Graves into the woods? Such a supposition was improbable. If the constable's murderer had betrayed any one to the police, why had he himself shot the policeman? Dexter sighed as he realized that his speculations were leading nowhere. Until he knew a great deal more than he knew now, he was groping vainly, without one enlightening clew to suggest the meaning of this strange and dark affair. It was wiser to leave off theorizing, and go after the woman.
There was nothing further to detain him. He paused only to prop the broken door in place, to prevent the intrusion of forest creatures, and then quit the cabin and struck off across the clearing.
Where his new quest would take him, he could not foresee. In all probability he would have to travel for some distance through the dense forest. Susy, the pony, was sure to prove more or less of a hindrance on such an expedition, and moreover she was tired after her long journey that day across the pass. He had previously unsaddled her, and she would do well enough by herself in the sheltered gully by the brook. So he mercifully left her behind, and set forth on foot.
The trail of the small shoes was easily followed. For a distance the woman had continued her headlong course, but the underbrush was too thick for heedless going, and it was soon evident that she had been forced to moderate her pace. Still she had kept on as fast as darkness and difficult ground permitted.
By the accumulated signs along the way the policeman knew that she traveled without a light, groping her path as best she might. Frequently she had stumbled over some unseen obstruction and now and then walked blindly into a tree trunk or windfall. And in the denser thickets spatterings of snow told how invisible branches had swished back in her face.