The biggest question in Boston remains: Who did it?

Runner John Ounao crying when he finds friends after several explosions rocked the finish of the Boston Marathon in Boston, Massachusetts, on April 15, 2013. Credit: Getty Images
Runner John Ounao crying when he finds friends after several explosions rocked the finish of the Boston Marathon in Boston, Massachusetts, on April 15, 2013. Credit: Getty Images

Investigators said that two bombs that tore through the crowd at the Boston Marathon finish line Monday may have been fashioned out of shrapnel-filled pressure cookers that were transported in black nylon backpacks.

Boston doctors treating the wounded told reporters today that several of the victims were maimed by what appeared to be pieces of plastic and metal. The fragments were removed during surgery, and turned over to authorities.

Federal Bureau of Investigation Special Agent Richard DesLauriers, who is heading up the investigation, said the pressure cooker bombs may have also contained ball bearings and nails.

As of this evening, no one had taken responsibility for the bombings, and investigators had made no arrests in connection with the attack, which killed three people and injured more than 170. The explosions happened around 2:50 p.m. Monday near the finish line of the Boston Marathon, on Boylston Street.

Authorities said they had received more than 2,000 tips as of noon, many of which were reviewed by 5 p.m.

“The investigation in its infancy. We will thoroughly review each and every piece of evidence,” DesLaurier said, also pleading with the public to provide more information.

The FBI is looking for people who might have seen or heard suspicious activity, including someone carrying a dark, heavy bag near the site of the blasts before the explosions. DesLaurier asked people to inform investigators if they heard any noises similar to an explosion in the days before the attack, as they may indicate a practice blast, and also if anyone overheard discussions a possible attack on the Boston Marathon.

“The range of suspects and motives remains wide open. We’re asking for tips from anyone who may target the event,” he said.

Forensic experts are reconstructing the suspected explosive devices at an FBI lab in Virginia to determine its components. More information is expected during a media briefing this afternoon, but in the meantime DesLaurier asked the public to “remain alert.”

Boston Mayor Thomas M. Menino joined officials at the briefing this evening, commending civilians and emergency respondents for their assistance.

“We are Boston. We are one community and we will not let terror take us over,” he said.

Follow Morgan Rousseau on Twitter: @MetroMorgan
Follow Metro Boston on Twitter: @MetroBOS



News
Entertainment
Sports
Lifestyle
Local

Brooklyn man charged in roommate's stabbing death

A Brooklyn man accused of violently stabbing his roommate to death on Monday is in police custody and faces murder charges.

International

Dinosaurs could have survived asteroid strike

It turns out there is a good and a bad time for the planet to be hit by a meteor, and dinosaurs were just unlucky.…

National

OkCupid admits to Facebook-style experimenting on customers

By Sarah McBrideSAN FRANCISCO (Reuters) - OkCupid, a top U.S. matchmaking website, intentionally mismatched users to test its technology, the IAC/InterActive Corp service said on…

Local

MTA fares still increasing 4 percent in newly…

The agency said the 4 percent increases, previously announced in December, will remain steady even as the MTA deals with increasing labor costs.

Movies

Interview: Brendan Gleeson on the way 'Calvary' depicts…

Brendan Gleeson talks about how his new film "Calvary" began over drinks and how his character here is the opposite of the lead in "The Guard."

Movies

'Get on Up' producer Mick Jagger on the…

Mick Jagger, a producer on the James Brown biopic "Get on Up," talks about the time had to tell the singer some bad news and his favorite JB record.

Television

'Glee' star Lea Michele to appear on 'Sons…

"Glee" star Lea Michele has been confirmed as a guest star in the final season of "Sons of Anarchy."

Television

TV watch list, Monday, July 28: 'The Bachelorette'…

See Andi Dorfman make her big choice on tonight's 'Bachelorette' finale.

MLB

Angelo Cataldi: Ryan Howard deserves better from Phillies

Just last week, Ryan Howard endured the embarrassment of a benching that was inevitable, and yet still shocking.

NFL

Larry Donnell has inside track in Giants tight…

Little-known Larry Donnell of Grambling State currently has the inside track, as the second-year player has received the bulk of the first-team reps.

NFL

Computer to Jets: Start Michael Vick over Geno…

Jets general manager John Idzik says the choice of who starts between second-year quarterback Geno Smith and veteran Michael Vick will be a “Jets decision.”

MLB

Yankees looking to trade for Josh Willingham: Report

CBS Sports’ Jon Heyman reported Sunday the Yankees are interested in Twins outfielder Josh Willingham.

Travel

Glasgow: Hey, hey, the gangs aren't here

This European city has done a good job getting rid of its more violent residents and revitalizing with artists.

Education

Babson College tops list of best colleges for…

Money magazine has just released its inaugural list of "The Best Colleges for Your Money" -- and the answers have surprised many. Babson College, which…

Education

NYC teens learn how to develop apps during…

Through a program sponsored by CampInteractive, the high schoolers designed their own community-focused apps.

Tech

The Ministry of Silly Walks app is both…

Monty Python have dug into their back catalogue for cash-ins once more, but with the Ministry of Silly Walks app, they've made something that's fun too.