SCOTT SIMON, HOST:
People who knew Dzhokhar Tsarnaev just have a hard time squaring the man they knew, with the violence in Boston. Sierra Schwartz went to Cambridge Rindge and Latin high school with the suspect, who's now in custody.
SIERRA SCHWARTZ: The Dzhokhar that I knew at the time was friendly, quiet but not in a - alarming way. He was just - you know, soft-spoken but very - you know, funny, very sweet, wouldn't harm a fly; someone that you would want to talk to.
SIMON: NPR's Tom Gjelten has been learning more about the suspects, and he joins us now. Tom, thanks so much for being with us.
TOM GJELTEN, BYLINE: Good morning, Scott.
SIMON: Just a few days, of course, there was the horror and the grief of the bombings; and the questions about who might have been behind them, and why. Now, there might be a few hard answers to some of those questions. Give us some idea how the police figured that out.
GJELTEN: It just took four days, Scott, and I think that we have to agree that that's a pretty impressive police achievement. And I think the reason that they were able to do it was, they just applied tremendous manpower to this effort. The key was to look at all those photos and video that they had at the finish line; and to try to find somewhere in that picture, somebody placing a bomb at the finish line.
And in order to do that, it took thousands and thousands of man hours. The key was, they eventually did, in fact, see two people that struck them as suspicious. But the key was when they found, in other footage, those two people walking together down the street. They walked together down the street and then coincidentally, one of them ends up at one bombing site; the other, at the other bombing site. So they had photos, and then they were able to go to the public and say, do you know who these are? And people knew who they were.
SIMON: Of course, the underlying questions now are just being turned over, and President Obama raised them in his remarks last night.
GJELTEN: Yes, he did. He actually said - the key question here, he raised - in his own words, he said: Why did young men who grew up and studied here, as part of our communities and our country, resort to such violence? That's - I think that question goes to the heart of us as an American nation.
We like to think that being integrated into this country - being welcomed, accepted, becoming part of a diverse community - really changes you. And yet it didn't change - or appears that it didn't change these young men. The other question he raised was - in his words, again - how did they plan and carry out these attacks, and did they receive any help?
Of course, that is very important. Scott, these two young men made bombs that were crude. And, you know, how many times did I have people this week saying, you and I could have made those bombs. But I'm not sure that I could have made a bomb. How do you really make a bomb and...
SIMON: And crude bombs can be, as we have both learned, terribly effective, anyway.
GJELTEN: So how did they do this? Did they get any help? So there are a lot of questions that remain to be answered here; particularly, how did these men become so radicalized that they were willing to do this?
SIMON: Officials have assured the public that everybody is safe. Can they be sure that there's not some conspiracy that's wider?
GJELTEN: I think what they meant when they said that, Scott, is that this immediate plot, they have found the people responsible for those bombings. They cannot be 100 percent sure that there weren't other people behind them, that they didn't receive any help, that there may be other activities going on. I think that comment was directed to the people of Boston, but I don't think they can be 100 percent sure yet, that there isn't more behind this.
SIMON: Do we know anything about these two young men yet, that might help explain some of those questions?
GJELTEN: You know, Scott, I think some of the most intriguing information that we learned was reported yesterday by our colleague Laura Sullivan, who talked to three friends of the wife of Tamerlan, the older of the two brothers. And what she learned from those conversations was that he had, in recent years, become a pretty troubled young man; became angrier, more distant, more alienated, was very hard on his wife.
His wife was a Christian. He insisted that she convert and over time, insisted that she become more devout. So I think that, you know, the focus right now is on him, the older brother, and the question of whether he may have influenced his younger brother, in some way.
SIMON: Yeah. And the priority in the investigation right now?
GJELTEN: Well, right now - obviously - they're waiting for Dzhokhar to get better so they can interrogate him, find out what he can share with them. They'll, obviously, want to talk to the wife of the older brother, and anyone else who knew them.
SIMON: NPR's Tom Gjelten, thanks so much.
GJELTEN: You bet. Transcript provided by NPR, Copyright NPR.