They were inspired to the act by a desire to get away, to flee from the scene of their crime.

They must believe that we were left helpless, unable to pursue them, or create alarm.

Yet if it was Kirby, why had he fled so swiftly, making no effort to take Rene captive also?
It was she he was seeking; for the purpose of gaining possession of her these murders had been committed.

Why, then, should he run away when he must have known the girl was already in his grasp?
The same thought apparently occurred to her.
"You--you believe that Kirby did this ?" "What other conclusion is possible?
We know that he passed us on the steamer--Sam saw him plainly.

It was his man, Carver, whom we found dead in the hut.