Then the Lord said to Cain, “Where is Abel your brother?” And he said, “I do not know. Am I my brother’s keeper?” 10 The Lord said, “What have you done? The voice of your brother’s blood is crying to Me from the ground. 11 Now you are cursed because of the ground, which has opened its mouth to receive your brother’s blood from your hand.
God didn't seem to know where Cain was.
Interesting.