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

NYPD looking for man they say assaulted elderly…

      The New York City Police Department is asking for the public's assistance in locating a Hispanic male 20's wanted in connection with…

Local

Three arrested after allegedly assaulting off-duty officer in…

Three men were arrested early Saturday morning after allegedly assaulting an off-duty officer at a Bronx bodega, and the NYPD is asking for the public's…

Local

Healthcare union creates vibrant West Indian Day Parade…

Volunteers worked almost around the clock through the weekend, putting the flashy finishing touches on hundreds of costume pieces 1199SEIU members will wear while marching…

National

Top 10 most hipster college campuses

Hipsters are everywhere these days. You can't walk down the anywhere anymore without seeing a pair of skinny jeans on a handlebar mustachioed 20-something, a…

Arts

Theater: Discouraging 'Poor Behavior'

Theresa Rebeck's latest off-Broadway play, about two couples sparring on a weekend getaway, repeats a few mistakes of her past.

Gossip

Chef Todd English arrested for DWI in the…

Celebrity chef Todd English is facing DWI charges after a traffic stop on Sunday.

Movies

Box office: 'Guardians of the Galaxy' is 2014's…

This weekend "The Guardians of the Galaxy" passed the fourth "Transformers" movie to become the highest grossing film of 2014.

Gossip

Spears back with controversial ex?

Is Briteny Spears back with Adnan Ghalib?

Sports

Novak Djokovic feeds off US Open crowd to…

Novak Djokovic isn't a native New Yorker, but he sure knows how to use the U.S. Open crowd to his advantage.

NFL

Odell Beckham still 'weeks away,' Tom Coughlin angry…

Giants head coach Tom Coughlin has fought a losing battle against the media all preseason over the status of wide receiver Odell Beckham Jr.

NFL

3 things we learned in the Giants preseason…

The final score didn’t matter — a 16-13 win by the Giants — but it would’ve been nice to finally see Big Blue’s new-look offense get on track.

NFL

NFL Power Rankings: Seahawks, Broncos, Patriots, 49ers start…

NFL Power Rankings: Seahawks, Broncos, Patriots start at top

Education

These college students think breakfast is the most…

  It should be no surprise that the city that never sleeps is also home to the most students who like to order food in…

Sex

When it comes to dating, height matters

Does a man’s height really matter when it comes to dating? Unfortunately - according to a new study - the answer looks like it’s yes.…

Travel

10 free apps to make traveling easier

Finding the nearest bathroom, calculating currency exchanges and locating your departure gate must have been difficult for travelers of previous generations. But we wouldn't know,…

Travel

How to get a seat upgrade to business…

It used to be much easier to upgrade your coach seat to business or even first class, but rigid rules and tighter schedules have made…