I was initially tempted to just let the Matthew Todd Miller story sit; we have absolutely nothing beyond the KCNA report from two days ago which is reproduced in full below. (As a number of outlets have noted, they probably inverted the order of his name).
However, there is a simple if cynical theory of what happened that is worth putting up for consideration: that the North Korean authorities themselves recognize that there must be something wrong with anyone seeking asylum in North Korea. The documentary film Crossing the Line, which focuses on two of the four American military defectors from an earlier era—James Dresnok and Charles Jenkins—pretty much confirms this theory (the other two defectors were Larry Abshier and Jerry Perish). Dresnok, in particular, is not an appealing character to say the least.
More seriously, North Korea’s objectives vis-à-vis the detainees and the reasons why some are treated differently is an issue that we have addressed in some detail; we provide a few links here to earlier posts on the issue If the little information we have is correct, the North Korean authorities are likely to get rid of Matthew Miller as soon as they can.
Detainees and Envoys (April 2013; on the possible North Korean motive of securing visits by high level envoys)
Detained Americans: Not-So-Innocents Abroad (September 2013; brief outlines of the American detainees)
Merrill Newman "Confesses" (November 2013)
Why is Kenneth Bae Treated More Harshly than John Short (March 2014)
KCNA Report on Putting American in Custody
Pyongyang, April 25 (KCNA) -- A relevant organ of the DPRK put in custody American Miller Matthew Todd, 24, on April 10 for his rash behavior in the course of going through formalities for entry into the DPRK to tour it.
He had a tourist visa for the DPRK, but tore it to pieces and shouted hoarse that "he would seek asylum" and "he came to the DPRK after choosing it as a shelter." This was a gross violation of its legal order.
The relevant organ put him in custody after taking a serious note of his behavior, and is now investigating the case.