ROBERT MUELLER

I know when I was here prosecuting homicides in the District of Columbia, one of the most effective units here was the cold case squad, which had on it FBI agents, as well as Metropolitan Police Department homicide detectives working together.

Leaking of classified material is a concern.

Secondly, not only have we put additional agents on counterterrorism, but we've also built up our analytical structure so that we're better positioned to analyze the information we have.

People talk about the Patriot Act that was passed immediately in the wake of September 11. What the Patriot Act did was break down the walls between the various agencies.

We had to address information technology in the ways we had not before and give the agents the tools that they need to do their job more efficiently and more expeditiously.

If you look at the 19 hijackers who came to the United States in Sept. 11 to commit those acts, if you'd looked at them before they got onto a plane, you could probably say the same thing. There were various levels of expertise, various levels of competence.

The 19 hijackers that came over here to commit the attack on Sept. 11, there were those that were at the bottom of the line. There were those who were the principal conspirators. There were those who were the pilot. Everybody has a role.

They're - FBI agents are some of the finest people you'll find anyplace in the country or the world. And I'm lucky to have the opportunity to work with them.

And so every one of us in the FBI, I don't care if it's a file clerk someplace or an agent there or a computer specialist, understands that our main mission is to protect the public from another September 11, another terrorist attack.

But we had - I think if you look at law enforcement 10 years ago, if you look at the challenges, the FBI was focused excessively on what was happening in the United States.

In the United States, it's the mandate of the FBI to gather information relating to terrorism, go out and collect it, to do the interviews, to do the investigative work.

There'll be differences of opinion in just about every intelligence analysis that you make.

And at that point, I think we all realized it was something tremendously tragic, probably a terrorist attack, and the next step was to go down to our command center and get things going.

It's because we need to determine who in this country is poised, positioned to commit terrorist acts.

I think around the world, our agents are the best collectors of information you'll find.

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.

I asked a Burmese why women, after centuries of following their men, now walk ahead. He said there were many unexploded land mines since the war.

I didn't know the organization, but the one thing you can say about the FBI, it's tremendously professional.

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.

As I said before, there are often disagreements as to what a particular set of facts mean. That is not at all unusual, and one shouldn't read into it more than is there.

We cannot go up on a wire. We cannot do a search without a judge on the FISA Court approving it and determining that we have met the standard that has been set forth by Congress in order to utilize these techniques.

So there is a foreign intelligence purpose for every one of our FISA warrants.

So without getting into the specifics, I can tell you that to the extent that investigation is a relatively important investigation and meaningful, the president would have been periodically briefed.

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.

In planning an attack, persons have various roles.