It's not really hacking....But how did he "gain illegal access to the affected costumers PC's"?? Sound's like something simple such as our old friend Sub7 was used to retrieve passwords
Personally I think he used a lot of social engineering , and installed a key logger on their system.

On a side note, Isellcrack4FBI has to be one of the best names I'v come across here at AO! Maybe I'm just easily amused?

LOL Thanks Conf1rm3d_K1ll