I believe he's a tour operator, between the two halves. He's got a history of feeding and taking photos of emaciated orphans for aid donations.
Yep. This is what I has read also. Though the situation in North Korea is dire, I believe there are some people are too good (or too foolish) that want to help the people there. Not to mention that he is a tour operator, he must visit North Korea often, that his trip is not scrutinized again.
Regarding his trial, I bet it will be totally unfair. He will just be another bargaining chip to continue Kim's madness and delusions. His so-called "confessions" must be taken under torture.
Nevertheless, if US wants to destroy North Korea using agents, why use a Christian agent? Christians are already widely prosecuted in North Korea, it will be foolish to use a Christian men, where they will be widely pressed and widely scrutinized. The agent's cover and profile is not good if he is a Christian in North Korea, not to mention his humanitarian aids.
If US had agent in North Korea, he/she must be a North Korean, probably high-ranking, and has "close" ties to Kim.