The Murder of Abel by Cain

From Land of the Lion and the Sun [p. 133]: "One day Cain saw Satan killing a raven with a pointed black pebble. Cain picked up the stone and cut the throat of his brother with it, and then washed his hands. But the stain was still on his hands, even when he had washed his hands day after day. And so long as Cain lived, he was never able to get rid of the blood of his brother from his hands."