NOEL KING, HOST:
One person is now in federal custody after a nationwide bomb scare. The Justice Department will hold a news conference later this afternoon to share more details. Now, this news comes on - follows the discovery of two more potentially threatening packages this morning. One of them was addressed to New Jersey Senator Cory Booker, the other to former Director of National Intelligence James Clapper. NPR's national justice correspondent, Carrie Johnson, has been following this fast-moving story. Hi, Carrie.
CARRIE JOHNSON, BYLINE: Hi, Noel.
KING: So what do we know about the person now in custody?
JOHNSON: Well, not much. A law enforcement source tells me it is a man based in Florida. We don't yet know his name or his background, or, importantly, whether he acted alone. We also don't know whether this person was motivated by politics or personal reasons or some other reason. The Justice Department says it's going to hold a news conference at 2:30 p.m. Eastern Time to provide more details on this unfolding case. Only this morning, investigators found a package addressed to former intelligence chief James Clapper in New York and also disclosed that they had found a package in Florida addressed to New Jersey Senator Cory Booker.
KING: Well, a lot of attention in this case - it focused on Florida overnight. Local police there searched a mail facility. What were they looking for?
JOHNSON: Last night, authorities were searching a package sorting facility in Florida in Opa-locka, near Miami. The operating theory was some of the packages went through that facility and through the U.S. mail. They were looking for more devices, but also any other clues. And local TV in Florida is now beaming images of a strong law enforcement presence in Plantation, Fla., at a site that appears to be connected to the suspect in federal custody. A lot of manpower has been deployed nationwide, though - the postal inspectors, the FBI, the Bureau of Alcohol, Tobacco, Firearms and Explosives have been on the case, as well as local police in the Miami-Dade County area and also, of course, the New York City Police Department, too.
KING: And there's also some ongoing activity in Virginia, right?
JOHNSON: Yes. In Virginia, the bulk of the investigation there is at the FBI lab in Quantico, which has been analyzing some of these devices which look like homemade pipe bombs. They've been looking for clues for how the bombs were constructed, and they've also been looking for DNA or fingerprints the bomber may have left behind. No word yet on whether anything they have found in that analysis has helped lead them to this suspect in South Florida.
KING: Oh, that's interesting. We'll have to wait and see, I suppose. So, I mean, one notable thing this whole time is that none of these bombs have actually exploded, and so there's been some speculation that maybe they couldn't explode. They didn't have the capacity. What have investigators said about that theory?
JOHNSON: On the record, police sources and the FBI are declining to answer questions about whether these bombs could have presented a lethal threat to anyone. On background, overnight and earlier this morning, I was hearing law enforcement was inclined to think they did not present a lethal threat. There could be a reason for that. Some former bomb analysts at the ATF have raised questions about whether these devices included a key component that would have set them off, that would have detonated them. It appeared from the photos that were made public that perhaps these devices lacked that key component.
But nonetheless, police had been advising folks, as had the FBI, to be very careful when they were looking at any manila envelopes or any suspicious packages because they needed to be considered a potential threat. And they - law enforcement right now, even, is advising people to call authorities, call police, call the FBI if they see anything suspicious. Now, we know that the New York police commissioner, James O'Neill, said last afternoon that the device they recovered in New York that was addressed to the actor Robert De Niro did not pose a biological threat, did not contain anthrax or any material like that, but that authorities were still treating all of these parcels as potentially dangerous. And the analysis may not be done yet as to what's in all of these bombs - potential bombs.
KING: So law enforcement officials still have a long way to go here. NPR's justice correspondent, Carrie Johnson. Carrie, thank you so much for the update.
JOHNSON: My pleasure. Transcript provided by NPR, Copyright NPR.