That kid committed pre-meditated murder. For a kid that age to even think of that, and the way to hide it, fuck. And the fact that he killed someone who was 7 years old, when he's 15, some one so weak and vulnerable compared to him, says to me that he's a fucking sadist more than he is a nut-job. Cutting up the earings, and hiding them, sounds like something a serial killer does.
As for here comes the gaming flaming, the only thing that could link the game to it is that the kid is 15, which is the earliest possible statistical age for psychosis onset to begin. So if he took the notion of killing for loot a bit too far, as a part of an onset of insanity, which could have been influence by the online culture in the game, same as media motivated the John Lennon killing, then the game could be blamed. But for his psychosis to have developed to that point if it were the case, doesn't speak well of Vietnam's mental health awareness or facilities.
But looking at his actions, the fact that he cut the earings up could be either ritual, in which case he's a serial killer, or some serious amounts of nagging guilt, in which case the kid's crazy, I really don't know which he is from this information. But whatever it is, it's not a gaming addict.
TL

R? The kid is insane or a serial killer, gaming addiction had sweet fuck all to do with this.