TigerLikesRooster: They are vague about it, aren't they?
From the article:
"The North Korean National Security Agency has investigated the incident since it took place and concluded that rebellious forces had plotted the explosions targeting the exclusive train of Kim Jong-il."The article's source appears to be identifying the origin of the attack as coming from within the NK government itself and more specifically from within their own armed forces. People from outside the nation would not be labeled "rebellious" and neither private citizens nor ordinary government officials of the country would be labeled "forces".
--Boot Hill
Thanks