Boston bombing: ‘Someone knows who did this’

Updated
BOSTON - APRIL 15: A woman kneels and prays at the scene of the first explosion on Boylston Street near the finish line of the 117th Boston Marathon on April...
BOSTON - APRIL 15: A woman kneels and prays at the scene of the first explosion on Boylston Street near the finish line of the 117th Boston Marathon on April...
John Tlumacki/The Boston Globe via Getty Images

Federal law enforcement authorities have no new leads on who is responsible for what President Obama has called a “act of terrorism” in Boston. They are reaching out to the public for help.

“Someone knows who did this,” said Richard DesLauriers, special agent-in-charge of the FBI’s Boston field office. “Cooperation from the community will play a crucial role.”

Authorities had received over 2,000 tips as of noon Tuesday, DesLauriers said, but there have been no claims of responsibility. ”We are doing this methodically, carefully, yet with a sense of urgency,” DesLauriers said.

Three people are confirmed dead–including an 8-year-old boy–and more than 170 injured after two bombs exploded near the finish line of the race shortly before 3 p.m. on Monday.

Patty Campbell, whose 29-year-old daughter was one of those killed in the blast, gave a tearful statement to reporters outside her family’s home in Medford, Mass., on Tuesday. ”We are heartbroken at the death of our daughter, Krystal Marie,” Campbell said. She had just returned from identifying her daughter’s body. “She was a wonderful person. Everyone who knew her loved her. She was a sweet kid and friendly, always smiling. She worked so hard at everything she did.”

Mary Tunney, director of public relations for Boston University, confirmed to NBC News that the third person killed in the explosion is a graduate student at the university. She is a Chinese citizen; authorities are not releasing her name at this time.

The White House said that President Obama will be traveling to Boston on Thursday to attend an interfaith service dedicated to those wounded or killed during the attack. “We’re very pleased the president will join us to help us heal,” Massachusetts Gov. Deval Patrick said at the press conference.

Authorities elaborated on the few new details in the investigation, including that the devices were possibly stored in pressure cookers. DesLauriers said investigators believe the devices were stowed in a dark-colored nylon bag or backpack, which would have likely appeared to witnesses at the scene as “unusually heavy.” According to NBC News, bomb specialists describe the devices as “low explosive,”  and said they appear to have been composed of explosives and shrapnel containing BBs, ball bearings, and nails.

Over 27,000 runners from around the world and more than 500,000 spectators attended the event along the 26-mile route, the Massachusetts Emergency Management Agency reports.

There were more police officers assigned to the race this year than ever before, Boston Police Department Commissioner Ed Davis said at the conference Tuesday afternoon. “We were particularly concerned with the finish line this year,” he said, “and assigned more officers down in that area.”

Davis added that he feels his department “struck the appropriate balance” in securing the event prior to the attacks, but the nature of the Boston Marathon requires it to be open to the public. “When you have an event like this, you can’t lock it down like a military operation,” Davis said. “By the virtue of the type of event this is, it requires that you don’t turn it into a police state.”

Boston bombing: 'Someone knows who did this'

Updated