I find so little in this story that a discussion of it could yield anything? Often these types of stories crop up but to the extent they generate worthwhile discussion is dubious. The fact that it may generate more speculation than actual fact could lead this thread to be closed.
At this point the person detained has failed to properly clear customs
and that alone is a crime. It's obviously the only real reason being put forward, but there may be more suspicions unstated. The circumstances of his being where he was found also seem entirely without evidence other than he did indeed fail to clear customs
and was found where he was. I'm not seeing anything more to this story without some new factual information.