Fangs of Gold by Robert E. Howard — Read

It was a noise at the windows, a stealthy twisting and wrenching at the bars, that awakened him. He woke quickly, with all his facilities alert, as was his habit. Something bulked in the window, something dark and round, with gleaming spots in it. He realized with a start that it was a human head he saw, with the faint starlight shining on rolling eyes and bared teeth. Without shifting his body, the detective stealthily reached for his gun; lying as he was in the darkness of the bunk, the man watching him could scarcely have seen the movement. But the head vanished, as if warned by some instinct.

Harrison sat up on his bunk, scowling, resisting the natural impulse to rush to the window and look out. That might be exactly what the man outside was wanting. There was something deadly about this business; the fellow had evidently been trying to get in. Was it the same creature that had followed him through the swamp? A sudden thought struck him. What was more likely than that the Chinaman had set a man to watch for a possible pursuer? Harrison cursed himself for not having thought of it before.