April 16, 2013 10:10:47 AM
BOSTON -- Police and federal agents appealed to the public today for amateur video and photos that might yield clues to the Boston Marathon bombing as the chief FBI agent in Boston vowed "we will go to the ends of the Earth" to find whoever carried out the deadly attack.
Two bombs blew up seconds apart Monday at the finish line of one of the world's most storied races, tearing off limbs and leaving the streets spattered with blood and strewn with broken glass. Three people were killed, including an 8-year-old boy, and more than 170 were wounded.
A doctor treating the wounded said one of the victims was maimed by what looked like ball bearings or BBs.
Federal investigators said no one had claimed responsibility for the bombings on one of the city's biggest civic holidays, Patriots Day. But the blasts raised the specter of another terrorist attack on U.S. soil.
President Barack Obama was careful not to use the words "terror" or "terrorism" as he spoke at the White House on Monday, but an administration official said the bombings were being treated as an act of terrorism.
"We will go to the ends of the Earth to identify the subject or subjects who are responsible for this despicable crime, and we will do everything we can to bring them to justice," said Richard DesLauriers, FBI agent in charge in Boston. He said investigators had received "voluminous tips," were interviewing witnesses and were analyzing the crime scene.
Gov. Deval Patrick said contrary to earlier reports, no unexploded bombs were found. He said the only explosives were the ones that went off.
Across the U.S., from Washington to Los Angeles, police tightened security, monitoring landmarks, government buildings, transit hubs and sporting events.
The FBI took charge of the investigation, converging on a home in the suburb of Revere on Monday night. Authorities gave no details on the search. Investigators were seen leaving a building there early today carrying brown paper bags, plastic trash bags and a duffel bag.
They also repeatedly appealed for any video, audio and photos taken by marathon spectators, even images that people think might not think are significant.
"There has to be hundreds, if not thousands, of photos and videos" that might help investigators, state police Col. Timothy Alben said.
Boston Police Commissioner Edward Davis said investigators gathered a large number of surveillance tapes from businesses and intend to go through them frame by frame.
Investigators refused to give any specifics on the bombs and say, for example, where they might have been hidden or whether they were packed with shrapnel for maximum carnage, as is often the case in terror bombings overseas.