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Bomb Details Emerge in Boston Case Bomb Details Emerge in Boston Case
(about 3 hours later)
BOSTON — The explosives used to kill three people and injure 176 at the Boston Marathon on Monday were most likely some kind of “pressure-cooker” devices that sent sharp bits of shrapnel flying into victims in the vicinity of the blast, several law enforcement officials said Tuesday. BOSTON — The explosives that killed three people and injured more than 170 during the Boston Marathon on Monday were most likely rudimentary devices made from ordinary kitchen pressure cookers, except they were rigged to shoot sharp bits of shrapnel into anyone within reach of their blast and maim them severely, law enforcement officials said Tuesday.
Surgeons at several Boston hospitals told televised news conferences on Tuesday that the explosive devices had apparently been packed with small pellets and sharp “nail-like” objects that were designed to maim their victims. The pressure cookers were filled with nails, ball bearings and black powder, and the devices were triggered by “kitchen-type” egg timers, one official said.
The new details about the explosives emerged as President Obama announced at the White House that the F.B.I. was investigating the attack as “an act of terrorism,” but said that it was unclear if it had been carried out by an individual or a group, foreign or domestic. The resulting explosions sent metal tearing through skin and muscle, destroying the lower limbs of some victims who had only shreds of tissue holding parts of their legs together when they arrived at the emergency room of Massachusetts General Hospital, doctors there said.
Two of the three people who were killed in the bombing were identified by relatives on Tuesday: Martin Richard, an 8-year-old from Dorchester, and Krystle Campbell, 29, of the Boston suburb of Arlington. Law enforcement officials said the devices were probably hidden inside dark nylon duffel bags or backpacks and left on the street or sidewalk near the finish line. Forensic experts said the design and components of the homemade devices were generic but that the marking “6L,” indicating a six-liter container, could help identify a brand and manufacturer and possibly lead to information on a purchase.
Boston University officials Tuesday afternoon said the third victim was a graduate student there but the university did not release the name of the student because it said it is waiting for permission from the family. The student was watching the race close to the finish line, the university said in a post on its news Web site, BU Today. New details about the explosives emerged as President Obama announced that the F.B.I. was investigating the attack as “an act of terrorism,” and made plans to come to Boston on Thursday for an interfaith service at the Cathedral of the Holy Cross.
Representative Michael McCaul, a Texas Republican who heads the House Homeland Security Committee, said the authorities believe that the explosives were similar to improvised explosive devices that have been used against American troops in Iraq and Afghanistan. Mr. McCaul, a former federal prosecutor who received briefings Tuesday morning from Federal Bureau of Investigation and Homeland Security officials, also said that the authorities still did not know whether the attack was a foreign or domestic plot. But officials said they still had no suspects in custody and did not give the impression that they were close to making an arrest as they repeatedly noted that the investigation was in its infancy.
Richard DesLauriers, the special agent in charge of the F.B.I.'s Boston division, said Tuesday evening that investigators officially began recovering forensic evidence from the blast site on Tuesday morning. “The range of suspects and motives remains wide open,” Richard DesLauriers, the special agent in charge of the F.B.I.’s Boston office, said at a televised briefing on Tuesday afternoon. And no one has claimed responsibility.
“Among items partially recovered are pieces of black nylon, which could be from a backpack, and what appear to be fragments of BBs and nails, possibly contained in pressure cooker device,'’ he said at a news conference, adding that they would be sent to the bureau’s laboratory in Quantico, Va. “In addition, this morning it was determined that both of the explosives were placed in a dark-colored nylon bag or backpack. The bag would have been heavy because of the components believed to be in it.” At this stage of an investigation, officials said it was not unusual for there to be no suspects. But with the paucity of leads, Mr. DesLauriers and others pleaded with members of the public to submit any photographs or video that they may have taken at the blast site to help in the investigation. At the briefing, Mr. DesLauriers said that someone somewhere almost certainly heard someone mention something about the marathon or the date of April 15.
Mr. DesLauriers said that the investigation was “in its infancy,” and that there had been no claims of responsibility, leaving the range of possible suspects and motives “wide open.” “Someone knows who did this,” he said. “Cooperation from the community will play a crucial role.” Officials said that as of Tuesday afternoon, they had received more than 2,000 tips from around the world. As marathoners left through Logan Airport on Tuesday, security personnel reminded them of the importance of sharing their pictures with the F.B.I.
“This is a very complicated investigation,'’ he said. “It is going to be pursued methodically, carefully, diligently, but with a sense of urgency. We are barely 24 hours on into this investigation, so I would say that this is still in its early, early stages, and that’s the best way I can characterize it right now.” Counterterrorism specialists said that the authorities would aim to match the faces of any possible suspects, using facial recognition software, against an array of databases for visas, passports and drivers’ licenses. “It’s our intention to go through every frame of every video that we have to determine exactly who was in the area,” Edward Davis, the Boston police commissioner, said at the news briefing. “This was probably one of the most well-photographed areas in the country yesterday.”
A law enforcement official said at least one and probably both of the bombs were pressure cookers filled with nails and ball bearings and black powder that were detonated with rudimentary “kitchen-type” timers. The official said investigators believe the bombs were hidden inside bags or backpacks and left on the street or sidewalk near the finish line. Boston was deserted on Tuesday morning, not only because many of the runners and spectators were leaving town, but also because yellow police tape and metal barriers still marked off a nearly mile-long area encompassing the two explosion sites, one that the police described as the most complex crime scene they had ever seen.
A senior government official who had spoken with intelligence and law enforcement officials said Tuesday that there had been “no pre-attack chatter” detected by the government from members of Al Qaeda or other terrorist groups. In two intelligence briefings the official said he had received in recent weeks, “nothing was offered on this” type of attack. At the morning rush hour, the city’s subway system was uncharacteristically quiet, watched over by the police and SWAT teams. Stores on Newbury Street, Boston’s busy retail thoroughfare, were closed, and tables on the patio at Stephanie’s, a restaurant there, were still covered in dishes left there on Monday.
The official said that the intelligence agencies had begun to go back and examine communications they intercepted in recent weeks to determine whether they had missed anything. “Before the 2009 Christmas Day bombing attempt, they thought there was no pre-attack chatter,” said the official. “But there had been, but it had not been interpreted. Everything is now being looked at.” Among the three dead was an 8-year-old boy, Martin Richard of Dorchester. The boy had been watching near the finish line and then moved back into the crowd; the blast killed him and severely injured his mother and his sister.
Katharine Q. Seelye reported from Boston, and Michael Cooper from New York. Reporting was contributed by John Eligon and Jess Bidgood from Boston, Steve Eder, Ashley Parker, William K. Rashbaum and Mary Pilon from New York, and Mark Landler, and Michael S. Schmidt, Eric Schmitt and Abby Goodnough from Washington. Another spectator, Krystle Campbell, 29, of Arlington, Mass., also died Monday from injuries she suffered while watching the marathon, her grandmother Lillian Campbell said Tuesday.
Katharine Q. Seelye reported from Boston, and Scott Shane and Eric Schmitt from Washington. Reporting was contributed by John Eligon, Richard A. Oppel Jr. and Jess Bidgood from Boston, Michael Cooper and William K. Rashbaum from New York, and Mark Landler, Michael S. Schmidt from Washington.
This article has been revised to reflect the following correction:This article has been revised to reflect the following correction:
Correction: April 16, 2013Correction: April 16, 2013

 An earlier version of this article referred incorrectly to marathon jackets worn by some participants.   They were available for purchase,  they were not given to runners.  

 An earlier version of this article referred incorrectly to marathon jackets worn by some participants.   They were available for purchase,  they were not given to runners.