It is obvious that NK would try to argue its case if it participated in any investigation. But it is also obvious that the US or South Korea would also do this. Everybody has a stake in the outcome, and nobody in the world is above twisting facts in order to achieve their aims!
However, by leaving the DPRK, or anybody whose special agenda will not coincide with the American one on this (read China, perhaps Russia), the US and ROK control the story line. And the story line that is coming out seems to be extremely convenient for the US indeed!
As somebody pointed out above, this puts China in a dilemma over its approach to the DPRK and sanctions. But, in my view, more importantly, it adds a load of pressure on the matter of Iran, because now China is just protecting the "bad boys".
Of course, I was not part of the investigation, and therefore I cannot say whose torpedo it was. But I can say a few things:
1) I cannot trust an investigation conducted by only one side of the dispute, and away from the eyes and ears of any one who might not coincide with the agenda of the investigators.
2) Admitting to a friendly fire accident would be fatal to the interests of both the current ROK government as well as very damaging to US-ROK relations.
3) While accusing the DPRK of sinking the ship places the ROK govt under pressure to retaliate in some way, the long investigation has effectively provided a buffer, a period of calming, so that the "retaliation" can be conducted in a rational and controlled way. This solution, in fact, is ideal for the US, because the incident, regardless of its original cause and scope, can be put to use to further the global agenda pursued by the US, and not just simply American aims in connection with the DPRK and Northeast Asia.
