By then the thief must have determined that unless he took chances he
would be made a prisoner. He gave a sudden yell, and threw himself over
the gunwale of the boat. By chance it was the side toward the water, and
they heard the splash that announced his arrival below.

"Some fellow aboard, bent on stealing everything we had!" exclaimed
Bluff.

"Was it George?" gasped Will, aghast at the possibility of such
ingratitude.

"No; a white man. See! There he goes, swimming across the river!"

The light was not very good, but they could see a sort of phosphorescent
glow on the water, where some object was struggling for the opposite
bank.

Bluff half leveled his gun, when Frank shoved it aside.

"You wouldn't want to kill him, even if he is a desperate case. I guess
he got little or nothing. Let him go. The sheriff will be along after him
soon," he said.

"But what is that trailing after him, Frank?" echoed Will.

"Where?" demanded the other quickly.

"Why, look right there! And whatever it is, it's catching up with him
fast, too! I believe it must be an alligator!" exclaimed Will.