“SIGINT [signals intelligence] coming out of NSA [National Security Agency] and intercepts collected by frontline U.S. military intelligence units proved that bin Laden was indeed at Tora Bora [in Afghanistan, in December 2001]. The official history of the U.S. Special Operations Command indicates that U.S. Special Forces continued to collect hard ‘all-source’ intelligence, most of which was coming from SIGINT, that ‘corroborated’ bin Laden’s presence at Tora Bora from December 9 through December 14, 2001. Only after December 14 did the trail go dead, the official history indicates.”
– Matthew M. Aid, The Secret Sentry, Pages 226-227