Many leads, no suspects yet in deadly attack on Boston Marathon

Editor’s Note: Today’s The Takeaway is devoted entirely to information about and reactions to the attacks at the Boston Marathon.

Federal law enforcement officials now believe the deadly blasts at the Boston Marathon Monday afternoon were caused by explosives packed into something like a pressure cooker and then supplemented with metal fragments, like BBs, ball bearings or nails.

At least 176 people were injured by the twin explosions and three people were killed. The deceased include an 8-year-old boy, a Boston University student and a 29-year-old from Arlington, Mass.

FBI Special Agent In-Charge Richard DesLauriers said pieces of the bomb, as well as a black nylon bag that was believed to be holding the bomb, have all been taken to an FBI lab in Quantico, Va., where they will be analyzed for any possible clues.

But despite the progress that has been made, officials indicated the investigation remains wide open, with no definitive suspects, and called on the public to continue to send in photos and videos from the scene, moments before and after the blast.

“Someone knows who did this,” DesLauriers said. “We are doing this methodically, carefully, but with a sense of urgency.”

Gov. Deval Patrick urged Boston residents to remain vigilant in the days ahead. He said the Massachusetts National Guard would remain on the scene to provide security for the crime scene, as well as to assist with random bag checks on the T. Patrick said that would go on for another day or two.

But Patrick also cautioned about stereotyping, and jumping to conclusions, saying people should not “think about people by categories.”

The area around the bomb scene remains cordoned off and closed to the public. Police Commissioner Ed Davis said his force hopes to decrease the area that’s cordoned off over the next few days, but cautioned that some areas could be closed for days.

“We’re in the process of processing the most complex crime scene in our department’s history,” Davis said.

Anyone with information or photos they think may be helpful to investigators are urged to contact law enforcement. The public can call I-800-CALL-FBI with tops or if they have photos or videos they want to get to investigators.

“It’s our intention to go through every frame (of surveillance footage) to determine who was in the area yesterday,” Davis said.

DesLauriers, whose agency is leading the investigation as part of the Joint Terrorism Task Force, said law enforcement would do everything possible to get the answers to who perpetrated this attack and why.

“This is a worldwide investigation,” he said. “We will go to the ends of the Earth to identify to suspect or suspects who are responsible for this despicable crime and bring them to justice.”