What is the meaning and deeper significance of “Am I my brother’s keeper?” in Gen 4:9?

Literally it means, “Am I responsible for keeping track of my brother’s whereabouts?” or “Am I his caretaker or guardian, as if he were a child?” Particularly when Cain should have known that God was aware of his guilt, this revealed an arrogance and lack of repentance that one might find in a man capable indeed of killing his brother in cold blood.