How the U.S. tracks Islamic State threats at home

HARI SREENIVASAN:

Federal investigators believe they have managed to capture three suspected ISIS sympathizers before they launched an attack.

On Wednesday, U.S. law enforcement charged three Brooklyn men with providing material support to a foreign terrorist organization.

Two of the suspects allegedly planned to travel thousands of miles to fight under the flag of the Islamic State. If that didn't work, they threatened to carry out attacks in the United States.

New York City Police Commissioner William Bratton characterized the arrests, saying — quote — "This is real. This is the concern about the lone wolf."

We are joined now from Washington, D.C., by Andrew Grossman, who has been covering this story for The Wall Street Journal.

So, Andrew, how did these arrests go down? What kind of tools did they use to get them?

ANDREW GROSSMAN, The Wall Street Journal:

What we saw here is actually a fairly common pattern that law enforcement in the U.S. has been using against people who might be plotting to join ISIS or other foreign terrorist groups.

They first attracted authorities' attention online with a post on an Uzbek-language Web site about threatening to kill the president.

That got the attention of the Secret Service, other law enforcement in New York, and they began to, you know, keep an eye on these guys, eventually put them in touch with an informant, who worked with them, sort of sussed out what their intentions were.

And then, as they got closer and closer — at one point, one of the — these — these men was going to go get on a plane at JFK. That is when they came in and made the arrests.

HARI SREENIVASAN:

So, what about the possibility that, if they didn't, say, make a threat to the life of the president, that they could have gone undetected altogether?

ANDREW GROSSMAN:

Well, that's the big worry here.

You know, I think the proliferation of online propaganda is really a double-edged sword here.

You know, it's luring people like this into — into — to get them — it gets them interested in going to join one of these groups. But, on the other hand, authorities can see a lot of that traffic.

They can see when people are getting in touch with someone overseas who might want to help them travel.

So, you know, it is — it's — that is the big worry, though, is these lone wolves, as opposed to known wolves, as law enforcement has started calling them.

The known wolves, at least they can sort of see and they keep an eye on.

The lone wolves who might be radicalized by that propaganda and might go carry out an attack here are the big worry for law enforcement.

HARI SREENIVASAN:

And there's also been concern that the known wolves list is so large that we just don't have the bodies to keep up and do surveillance on all these potential threats.

ANDREW GROSSMAN:

Right.

I think it's hundreds of thousands on the U.S.' terrorist list alone. And the fear also is, you know, the U.S. has about 150 people who have traveled — attempted to travel or traveled to fight in Syria, not all for ISIS, but for various groups there.

The Europeans — for Westerners as a whole, it's about 3,400. And, now, that's a worry for law enforcement because a lot of those people are from countries that have visa waivers.

They can easily come to the U.S., or they can carry out attacks in Europe.

So it's a much bigger problem for law enforcement in allied countries, as we saw in France not too long ago.

HARI SREENIVASAN:

So, is this a shift in a law enforcement approach?

We were talking in the newsroom this morning this almost seems like the PreCrime division from the movie "Minority Report," trying to figure out before you commit a crime, stopping you.

ANDREW GROSSMAN:

Right.

And this has actually been somewhat controversial, this use of informants. And the FBI has been doing this, to some degree, since not long after September 11.

A lot of these cases — you know, there have been cases where an informant or an undercover FBI operative gets in touch with someone who is — appears to be interested in doing, carrying out some sort of attack, and really walks them through the steps necessary to get them to the point where they're — almost in certain cases have their hand on the trigger of what they think is a bomb, as we saw, for example, in a case in Chicago.

And then, once they go push that trigger, it turns out that the whole thing is a setup.

And you know, that — some of that has been controversial. The FBI says they really try to stay — they do stay on the side of letting the target, the suspect drive the operation.

But, you know, there — it's a very close, fine line between that and entrapment.

HARI SREENIVASAN:

All right.

Andrew Grossman of The Wall Street Journal, joining us from Washington, thanks so much.

ANDREW GROSSMAN:

Thanks, Hari.