handlers. >> they were more or less shocked to hear it. they asked me to go over details, hours and hours describing every single second of that encounter. so they were guessing at the time that it will be an attack similar to the nairobi and tanzania in 1998 or again the "u.s.s. cole" in 2000. no one even guessed it's going to be on the magnitude of 9/11. >> there was a certain amount of chatter that something big might go down but the details of the plot were kept really quite secret. >> reporter: on september 11th, aimen dean was walking down a busy street in central london when he wait a minute upon a crowd. >> basically i saw lots of people congregating around a shop window, which was at the time one of the shops that sells big tvs and i looked at it and i saw one the towers of the world trade center on fire. and the first thing that came to my mind was this is al qaeda, no