“likely a set up.”
How do you set a person up to distribute child porn?
some one can remotely access you computer or breaks into the computer itself and access it over the internet. doubtful that is what happened. my guess is he has been doing it for years with out any repercussions. the service provider probably up dated its monitoring programs noticed that the computer was accessing a known server for distribution of child porn.
Not just child porn, but any type of illegal media ( such as copyrighted movies, mp3's , etc.. ). If you can gain access to someones computer, you put the files in a hidden folder. You then install something like Emule to share those files to the Internet. You have that running in the background. Most people are not aware of what programs their computers are running in the background.