Take Wiley's Note to Mathias Shaw in Stormwind.
I wonder what Wiley meant when he mentioned the Stonemasons. Perhaps that was a slip of tongue. Could the Defias gang be related to the Stonemasons? Only one man would know for sure: Mathias Shaw, head of SI:7. Show him Wiley's Note and see if he has anything to add to this growing mystery. If you have trouble finding Shaw, check the Barracks in Old Town.