DAVID GREENE, HOST:
And let's bring in another voice here. It's actually another Johnson. It's my colleague, NPR justice correspondent Carrie Johnson. She's been listening. And, Carrie, good morning.
CARRIE JOHNSON, BYLINE: Good morning, David.
GREENE: You know, one thing we just heard there from Senator Johnson, he mentioned that the attackers in San Bernardino inspired by perhaps a terrorist group overseas. And this seems in line with what President Obama told us last night - no evidence that the killers were directed by a terrorist group, no evidence that there's a broad conspiracy here at home. But he did call it terrorism. What - update us on, if you can, on this investigation.
JOHNSON: David, the attorney general, Loretta Lynch, says authorities have already conducted over 300 interviews and searches in multiple locations. We now know there have been two searches of the Riverside, Calif., home of a former neighbor of the male shooter, Syed Farook. Authorities believe some years ago, this neighbor purchased the two assault-style rifles that were used in the attack. But here's the thing. They FBI wants to talk to this man, but he's apparently checked himself into a mental health facility. Law enforcement has a lot of questions for him. There are also a lot of open questions about what the family may have known - Farook's mother, who lived with the couple and their 6-month-old baby. Family lawyers say all the family members are cooperating with authorities, but there are big questions about why no one noticed there were 12 pipe bombs in the garage, thousands of rounds of ammunition in that garage, and also big questions, David, about who in this couple, the male or the female, Tashfeen Malik, may have radicalized whom.
GREENE: You know, you bring up the pipe bombs and the stuff that was in this home and why it wasn't noticed. I think that has led many Americans to wonder why people, like these two who would carry out such an attack, are so hard to track. I mean, could the FBI do more surveillance? Are there limits there?
JOHNSON: So there are limits, David. The FBI operates under domestic guidelines for investigations here in the United States. Those are of legacy of some of the unfortunate and sometimes unconstitutional overreaching federal officials did in the civil rights era, for example, against Dr. Martin Luther King, Jr. So the FBI director, Jim Comey, says they need some kind the predicate, some kind of information to open an investigation. You can't just go snooping around on a hunch. Now, since the San Bernardino attacks, some critics have called on the FBI to lower the level of information they need in order to open an investigation, but that would be enormously controversial, both politically and in terms of national security. And as for surveillance, of course, the laws have changed here in the U.S. since the Edward Snowden NSA leaks. The U.S. no longer collects and holds phone records in bulk. Now the phone companies hold those records, and the government has to ask permission for them. We're told that may slow the process down a little bit, but the U.S., of course, has a lot of other electronic surveillance tools, too. The challenge here with the threat evolving from large scale al-Qaida attacks to these kinds of do-it-yourself operations, it's really hard for authorities.
GREENE: All right, that's NPR's Carrie Johnson updating us on the investigation of the San Bernardino attack. Carrie, thanks very much.
JOHNSON: You're welcome.
GREENE: And you are listening to Carrie. You hear her reporting here on MORNING EDITION from NPR News. Transcript provided by NPR, Copyright NPR.