"Now the big question in my mind is this. Who at the CVG wrote the letter? Was it the project manager, the vice President or the president Rodolfo Sanz"

As I recall, Sanz has a "gag order" in effect on CVG employees, so it is very likely that anything coming from CVG would at least be with explicit approval from Sanz. I agree that it is good news -- about time that CVG respond.

I am curious about the question posed by others: why did KRY wait to release the news of the letter?

I seriously doubt that it was a decision made by KRY on its own. Sure, the letter would have been covered by the recent protective order, but only to the extent that the company would not have otherwise released the letter, which indicates to me that there is more than meets the eye here.