I would say in just about every investigation we have, there will be differences of opinion, where you have partial facts, as to what those facts mean.

And from the moment that we realized it was a terrorist attack, there isn't an agent or a support person in the FBI that wasn't committed to bringing to justice those who were responsible for this.

In the context of September 11, there were so many that lost their lives that - how do you single out one person? There were so many acts of heroism that day from so many people, whether it be firemen and police officers in New York and our agents also.

Prior to the passage of the Patriot Act, it was very difficult - often impossible - for us to share information with the Central Intelligence Agency, with NSA, with the other intelligence agencies, and likewise, for them to share information with us.

What we bring to the table is not only our 56 field offices in the United States and our number of resident agencies, but also we have 45 legal attaches overseas.

In the last 10 years, in narcotics task forces, in a number of violent crime task forces, we've worked very closely together with state and local law enforcement.

I was in my office when - on 9/11. I think I had a number of meetings scheduled. I was just getting to know the bureau. And somebody walked in and said the first plane had - or a plane had struck the World Trade Center, one of the towers.