Sounds interesting but still its hard to believe, and why would this agency will take so much effort just to identify satoshi his not even a criminal still this is another theory and not proven yet.
Since when NSA is seeking criminals only ? They monitor the world just because they can do it, and they try to identify / prosecute anyone they think is a harm to them, their agenda or whatever. So I think it is not that far fetched to imagine they really want to know who Satoshi is, because he has created something that could do harm to the global
enslaving financial system.