Doesn't this system still lead to a large trail of emails going back to Pakistan (assuming the courier didn't go all the way into Afghanistan to send each email). Presumably, some of the computers that were on the receiving end of those emails have been seized by US intelligence in various raids. The IP of the sender would be easy to trace for the CIA, and the content of the emails would have at least indicated that the sender was in a key decision-making position within the organization.<p>Without some other security steps, like VPNs or proxies, the US would have certainly been able to trace the country of origin of these communications.