Well if any of you guys watch One Tree Hill what is that kid huant Nathans Dad?

Answer 1

That is his brother Keith when he was younger, who he killed.

Answer 2

Nathan's dad is Dan. He had a brother, Keith, who he shot in a school shooting. So, Keith's dead now. Nobody knows that Dan actually killed his brother, except the person who wrote "MURDERER" on Dan's wall.

Now, however, Keith is haunting Dan. Though, the image of Keith is from when he was a child. :)