I thought of knocking on the window, but I had a better idea.
Went back inside and disconnected the modem from the router (just in case), and booted up a LiveCD of Puppy Linux. I created a ad-hoc wireless network as bait and waited. 5 minutes later someone was connected. The user connected was Darren-Lap. I got his IP address and managed to SSH into his laptop without any password prompts.
Quick Google to see if I could send him any messages through the Terminal. Found a method and sent him a message saying if he didn't leave in 5 minutes there would be consequences. His reply: "F**K YOU! Suddenly the firewall was getting a lot of hits.
A simple "sudo rm -rf /" command sorted him out. (http://is.gd/fE7cL - demonstration)
So here's a tip: Try to hack into my network, and be prepared to lose.