ROBERT SIEGEL, HOST:
From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.
MELISSA BLOCK, HOST:
And I'm Melissa Block. The two bombs that detonated yesterday in Boston were packed inside pressure cookers - a lethal concoction of explosives, nails, ball bearings and timers. That's according to officials familiar with the investigation. But investigators say they do not yet have enough evidence to know whether this is a case of domestic or international terrorism.
Three people were killed in the blasts near the finish line of the Boston Marathon. More than 170 were injured, 17 of them critically. We begin our coverage this hour with NPR's Tovia Smith in Boston.
TOVIA SMITH, BYLINE: Bill Richard says his family is now simultaneously grieving and recovering. The attack on Boston, as he called it, claimed the life of his dear son Martin, just eight years old, and seriously injured his wife and daughter. Meantime, Patty Campbell struggled to contain her grief over the loss of her daughter, Krystle Campbell.
PATTY CAMPBELL: She didn't had to go. She was always smiling and friendly. I couldn't ask for a better daughter. I can't believe this has happened. This doesn't make any sense.
UNIDENTIFIED MAN #1: It's horrible what happened. I mean, stuff like that shouldn't be happening, especially on American soil.
UNIDENTIFIED MAN #2: It's sad, very sad.
SMITH: Bostonians did some grieving of their own at an impromptu memorial of flowers now covering one of the police barricades surrounding the crime scene that still stretches 12 blocks. Officials say it may be days before it's cleaned and reopened. The spectator barricades and flags from around the world that proudly lined the course yesterday became a twisted tangle on the street, splattered with glass and blood.
Val Mattna, who came from North Carolina to run the marathon, found the whole scene disturbing.
VAL MATTNA: It's just eerie. And it's like everyone just left. We walked by a restaurant and you can see everyone's dinners are still sitting there. I mean, they just cleared everyone out so quickly and it's like everything just stopped, because it did.
SMITH: Authorities say they began today to recover forensic evidence from the site, but FBI special agent in charge Rick DesLauriers says answers may take some time.
RICHARD DESLAURIERS: It's - this is a very complicated investigation. It is going to be pursued methodically, carefully, diligently, but with a sense of urgency.
SMITH: Authorities say they swept the perimeter of the race course twice yesterday and found nothing. But it's an open course and people can easily come and go, says Boston police commissioner Ed Davis.
ED DAVIS: This is a soft target. And so, anybody can go into a church service and do this type of thing. When you have an event like this, you can't lock it down like it's a military operation. It needs to be open to the public. It requires that we don't turn these events into a police state. We want you to live your life. We want you to be vigilant. There's no reason to not come into the city, but we do have a threat and we are working diligently to try to reduce that threat.
SMITH: Davis says public help is critical to their investigation. They're asking for anyone with photos or videos of the blast area to send it in. And FBI special agent DesLauriers implored people to call immediately if they know anyone who was talking about targeting the marathon or making bombs, and anyone who may have heard noise of explosions or saw anyone carrying a heavy, dark nylon bag yesterday.
DESLAURIERS: The person who did this is someone's friend, neighbor, co-worker or relative. Someone knows who did this.
SMITH: Meantime, the scores of wounded are facing what will be a long recovery. As Mass General chief of trauma surgery Dr. George Velmahos put it, many have been shattered physically and emotionally. He says four victims at his hospital had to have limbs amputated.
DR. GEORGE VELMAHOS: Almost all of them had such severe trauma in their lower extremity that it was beyond salvation, so I would consider them almost automatic amputees. We just completed what the bomb had done.
SMITH: Even trauma surgeons used to seeing large-scale catastrophes were overwhelmed, Velmahos says.
VELMAHOS: It is a devastating thing. It is extremely difficult to come to this, but mind you, the focus was on saving the life from bleeding.
(SOUNDBITE OF BOSTON SUBWAY ANNOUNCEMENT)
SMITH: Around the city, Bostonians are expressing similar resolve.
UNIDENTIFIED WOMAN: I don't think anyone wants to be here, but everyone wants to be here. This is what we do.
SMITH: Pam Fradken(ph) picked up a cup of coffee on the way to the train this morning and defiantly made her way into the city.
PAM FRADKEN: When you lie down, you give up, they win - whoever "they" is.
SMITH: Officials are vowing to get that answer. As one put it, we will go to the ends of the Earth to find those responsible for this crime and bring them to justice. Tovia Smith, NPR News, Boston. Transcript provided by NPR, Copyright NPR.
