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From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.
MELISSA BLOCK, HOST:
And I'm Melissa Block.
In downtown Boston today, 12 city blocks are a crime scene. At nearby hospitals, doctors are still treating dozens of victims of yesterday's bomb blasts, many with gruesome injuries.
We'll hear more about what doctors are seeing in a few minutes. First, an update on early leads in the investigation. NPR's Dina Temple-Raston has been covering that part of the story, and she joins us here in the studio. And, Dina, at this point, what have you heard about any possible suspects?
DINA TEMPLE-RASTON, BYLINE: Well, part of the process of finding suspects is ruling people out. And officials familiar with the investigation say state police, for example, last night, searched residents in Revere, Massachusetts. It was a consensual search of a home of a Saudi student, and this is someone who some media outlets have singled out yesterday as a suspect.
One official told me that while nothing is ruled out at this point, the student is now seen as a witness in the case, not a suspect. They didn't find anything in the search that would have linked him to the attack, and he was brought to investigators' attention when his injuries after the blast appeared different than the other injuries doctors are seeing.
He's still in the hospital. He's not under arrest. He's not under any sort of guard. And, again, he's being seen as a witness. Now, often people we think of as people of interest are, in fact, witnesses in a case. So we should expect to hear more of these kinds of people coming up as the investigation continues.
BLOCK: OK. But apart from that, no other ideas about any possible suspect.
TEMPLE-RASTON: No, no.
BLOCK: OK. What about the explosives themselves? We've been hearing about pressure cookers today.
TEMPLE-RASTON: Yes. Well, basically, it's one of those pots that you use often to cook rice, and pressure cooker bombs have traditionally been used by young jihadists to get bomb training in Afghan training comps. An al-Qaida online magazine called Inspire provided instructions on how to build pressure cooker bombs, but that doesn't necessarily mean that this is a foreign plot.
Instructions on the how to make this kind of bomb is all over the Web. In fact, white supremacists, on their website, have linked to the Inspire magazine directions to make this bomb. So officials are telling me that we should be careful not to read too much into that.
BLOCK: And what are officials telling you about how easy it would be to make a pressure cooker bomb like the ones we saw in Boston?
TEMPLE-RASTON: They're pretty easy to make. I mean, basically, you put in explosives like TNT into the pressure cooker. You attach a blasting cap. It can be detonated with a digital watch. For example, al-Qaida actually had a particular kind of Casio watch that it liked to use as a detonator. Or you can use a cellphone or a pager. Looks right now like these were actually detonated with Casio watches. That's what we understand.
Now, officials wouldn't say how these - exactly whether or not both these devices were detonated in the same way. But right now, it looks like it's one of this simple design.
BLOCK: And lots of physical evidence being collected at the scene that investigators are going to be looking through. What else will they be considering as they try to put this together?
TEMPLE-RASTON: Well, we're hearing that they have some promising leads, but no smoking gun. They expect this take - this case now will take weeks, not months, to solve. The thinking, as we've been reporting, is that this is a domestic or extremist attack. Again, this is not because - this has got to be this because officials can't get away from this idea of timing.
April is a big month for anti-government, right-wing folks. There's the Columbine anniversary. There's Hitler's birthday. There's the Oklahoma City bombing. There's the assault on the Branch Davidian compound in Waco. And these are all rallying points for these kinds of extremist groups. And the FBI still compares - comparing this to the Atlanta bombing case in 1996 during the Olympics, the Eric Rudolph case, which took months to actually solve.
BLOCK: OK. NPR's Dina Temple-Raston. Dina, thanks.
TEMPLE-RASTON: You're welcome. Transcript provided by NPR, Copyright NPR.
