No one mentions North Korea in relation to the Boston Marathon Bombing, even though they made a direct threat on the day of the bombing-
"Our retaliatory action will start without any notice from now," North Korea's state news agency KCNA said on Monday, noting actions would "start immediately."
Consider that North Korea had their own international Pyongyang Marathon the day before the Boston Marathon. The North Korean's are celebrating one of their faux high holy days- The Day Of The Sun- the birthday of their founding father Kim IL Sung on April 15th. One of their most important days of their year.
Its obvious that the North Korean's have the motive; but do they have the opportunity?
Well it just so happens that the only "China Town" in New England is in Boston and it is less than one mile away from the finish line. So unfortunately for the good people of China Town, it might make the place for an inconspicuous North Korean agent to try and meld in.
With all of these obvious connections, one would think that the Boston Marathon would have had greater vigilance; may be they have their focus in the wrong direction. It would seem as if they are still hunting to pin this bombing on Richard Jewell (the hero of the Atlanta Olympic bombing)
One key final aspect that puts this situation in the corner of a skilled special forces infiltrator is that the improvised explosive device apparently was made with local materials, but yet had sophistication in both in timing and directionality. Note that it was a low order explosive; that the blast was directional and aimed low (few windows were broken, and little shrapnel when vertical).
So does this guarantee that the North Korean's are responsible, NO; but it does mean that the authorities in Boston should have been actively considering the threat given how obvious the potential was. It is also telling that given the obvious threat potential that no one else is even mentioning the North Korean's as being the actor; maybe the payback is just to risky?
BTW, where was the missile launch that was expected on The Day Of The Sun? Maybe they had other things in mind?