Cain : where is Abel your brother ?

Genesis 4 KJV

9And the LORD said unto Cain, Where is Abel thy brother? And he said, I know not: Am I my brother's keeper?

10And he said, What hast thou done? the voice of thy brother's blood crieth unto me from the ground.

11And now art thou cursed from the earth, which hath opened her mouth to receive thy brother's blood from thy hand;

12When thou tillest the ground, it shall not henceforth yield unto thee her strength; a fugitive and a vagabond shalt thou be in the earth.