Genesis 4:9

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

1. Following Abel's murder, the LORD asked Cain where Abel was. (It seems fairly obvious that the LORD knows what has happened, and that this is the reason He asks Cain, but as with Adam and Eve's transgression, the LORD doesn't accuse and is apparently not angry. Instead he asks Cain a question, giving him the opportunity to voluntarily confess. Why does He operate this way? Is this, perhaps, a useful approach for parents to use with their children?)
2. Cain responded that he did not know, which was a lie.
3. Cain asked the LORD if he were Abel's keeper. (In other words, "why are you asking me?" which seems like a very arrogant response.)
4. Cain was not a nice guy; he was a murderer, a liar, arrogant, did not respect the LORD and apparently had a violent temper. It makes me wonder how he felt about other members of his family.