there was never any particle evidence. in fact, he planted evidence to mislead investigators. >> he would actually wear disguises when he went anywhere, to pick up a piece that was going to become a component in his bomb. >> i had only really seen that in foreign counterintelligence because spies have to be careful. they have tradecraft, and this guy was making up his own tradecraft. >> but, while he was doing that, he overlooked one very serious aspect of this, and that was the behavioral part. you can remove forensic clues, but you can't remove who you are. >> it was obvious that he was a reader and a writer. his grammar, his syntax, vocabulary was someone who was educated. >> one of the immediate things we had noticed, when we started working on unabomb as a task force, were all of those bombs that were placed in universities, university of chicago, at northwestern university and university of california, berkeley, not mailed to them, placed, so someone felt very comfortable being in those