I doubt that this letter was signed by Sanz but I have no doubt that Sanz knows of the letter and approved it. I'm sure the letter was for the bond holders court case so it makes sense that the confirmation should come from the company Kry has the contract with.

The question as to what is stopping Sanz from saying the same thing is a letter from Mibam is one we may never know. I believe it has to do with what ever is going on behind the scenes. Sanz sending the letter would change everything if there was any negotiations on a buyout or merger as the price would change as well as the need to do a deal.

There are as many theories as one wants to make up but we will never know for sure and we will certainly not know till this saga is over.