... they waited until ... THEY WERE OUT OF THE COUNTRY!
Possibly, but I personally belive the feds waited two days to see if they could ID them before anyone else.
They were clearly not successful and wasted valuable time not going public with their images when it was determined they were the suspects.
In addition, we know they have much better video/images of these two.
It begs the question, why would they release marginal images of these two when they have much better images?
What would be their motive of of sitting on the additional images/video?