Investigators in Boston blasts hunt 2 men from scene
By Pete Williams and Erin McClam, NBC News
(NBC) -- Authorities investigating the attack on the Boston Marathon focused Thursday on finding two men seen on camera, including one who set down a black bag and dashed away just before the bombs went off.
Investigators combed cellphone records in an effort to put a name to the men's faces. Law enforcement officials said that they were seen from several angles, including from a surveillance camera at a department store, and that one was seen talking on a cellphone.
The FBI distributed a photo to other federal law enforcement agencies of the men. The official described one of the men in the photo as about 6 feet tall and wearing a baseball cap that was white or off-white. He was spotted at the site of the second of the two blasts, which combined killed three people and hurt 176 near the marathon finish line Monday.
Investigators still had no conclusion about whether the attack was foreign or domestic terrorism. Three days after the blasts, a prayer service, interfaith and titled "Healing Our City," was to begin at 11 a.m. at the Cathedral of the Holy Cross. President Barack Obama, first lady Michelle Obama and former Massachusetts Gov. Mitt Romney planned to attend.
As Boston grasped for normal life, the city staged its first professional sports event since the blasts — a hockey match that the Bruins played against the Buffalo Sabres at TD Garden before 17,000 people.
Discovering who was responsible for the bombings could take some time, but investigators are able to construct a mosaic using the many images provided, forensic evidence and secret intelligence, explains NBC National Security analyst and former Director of the National Counterterrorism Center Michael Leiter. During the national anthem, the fans gradually joined in singing, and they sent up a deafening roar over the last few bars. One YouTube video of the moment had already been viewed more than 100,000 times.
In the investigation, authorities said that they had made significant progress. However, asked whether investigators knew the identity of the people of interest in surveillance photos, Gov. Deval Patrick said, "No." He declined to elaborate.
Forensic work from the blast zone has helped authorities identify major components of the bombs.
They were housed in metal containers — at least one an everyday kitchen pressure cooker — and studded with metal, including fine nails or brads, to make the devices more lethal.
The type of battery pack used typically powers toy cars and trucks, and tens of thousands have been sold in the past year alone, which would make it difficult to trace, said Benjamin Mull, vice president of the manufacturer, Tenergy.
The FBI lashed out at news organizations after some reported Wednesday afternoon that a suspect in the case was in custody.
As of Wednesday afternoon, 62 patients were still being treated in hospitals, 12 of them in critical condition. That was down from 65 in the hospital and 14 critical earlier in the day.
The three people killed in the attack were Lingzi Lu, a Boston University graduate student; 8-year-old Martin Richard of Boston; and 29-year-old Krystle Campbell of Medford, a Boston suburb.
A trauma surgeon said that doctors have pulled fragments as large as 2 inches, including pieces of wood, concrete and plastic, from the bodies of the injured, in addition to metal shrapnel from the bombs.
NBC News' Richard Esposito, Tracy Connor, Hasani Gittens and Michael Isikoff contributed to this report.