To mirror words you have said in the past. "I may not know much about secret agencies..." You are doing a very impressive job! As others have said, the cover story is very believable and you've played it off well. We as the reader buy into it.
My only critique is with the officers when they are banging on the door. When approaching any unknown situation, their stance is to have the gun holster unbuttoned, and their hand near the weapon when a door opens. A friend of mine used to be a police officer from a while ago, so it's pretty safe to say that technique has been around for many years.
This is a wonderfully believable story that keeps us all intrigued, word by word! You really are a fantastic writer!
