In the episode where Dexter gets his biological dad's will and goes to his house to pack up all his stuff and everything, you found out that the Ice Truck Killer (Rudy, Brian whatever you want to call him) dressed up as the cable guy for the old lady across the street from the house. I never really understood why he did that. Also, keep in mind that I've only watched the first season of the show, so no spoilers, please.