Dexter raised his head and called the superintendent's name, shouting with all the power of his lungs. He repeated the cry several times, but only echoes answered him from the mountainsides.
"Can anything have happened?" he muttered after a lengthy pause. He turned abruptly to Preston. "I want to look inside the cave," he said. "Go in ahead of me, please."
With the boy accompanying him, Dexter searched the cavern from one end to the other. But the place was empty, and he found no clew to tell him what had happened to his missing officer.
"How long have you been here?" he asked, when they finally emerged into the sunlight.
"I don't know," replied Preston. "About a half hour, I guess."
"There was no one here then?"
"Nobody."
"How'd you find the place?"
"Just accident." The boy glanced up in seeming frankness. "I was looking for—for—"
"For your sister," supplemented the corporal as the other hesitated. "You needn't be afraid of betraying any secrets. I know all about you."