[emokidx]

You can contact the people who deal with the cyber crimes branch and they can probably cut of his internet access. But I don't know how this works with different countries.

I mean if you both belong to the same country, you can contact your own police division.
While in the case of different countries if you contact your own police, I don't think they would contact another country's police just because some kid DDos'd someone's game server and also it probably depends on whether his own country's police is willing to do that.