out sourceing the hunt for bin laden. using cases of cash. >> we paid the enemy off to get them to surrender at times. we used cash as an ally tool. it was quite effective. >> reporter: within weeks, afghanistan is falling. bin laden is on the run. east to the mountains, nestled among the 14,000-foot peaks, a complex of save r caves known as tora bora. >> it was an excellent place to hide because bin laden would spend many years living in and around the region. he had a house with a small rudiment tri swimming pool, a bakery, a whole setup there and