Find the fucker who did this! Then go to the police. Make sure you find this guy before the police do:

Then, rent a van, get 4 of your buddies, and kidnap him when you see him walking on the street. Use one of those black headbag things so he doesn't see sh*t. As soon as you get him in the van, knock him out using some kind of drug or brute force, and then speed off to a remote location. Proceed to beat the shit out of him, and do whatever you please. Then drop him off at your local police station unconcious! Be sure to post 0wn3d pics on the web.