NEW: The FBI gets a "large volume" of calls after releasing photos of suspects, official says
"Somebody out there knows" the 2 suspects in the case, an FBI agent says
The 2 men walked away from the scene "pretty casually," a federal official says
At an interfaith service, Obama tells Boston attackers: "We will find you"
After three days of poring over photos and video, investigators appealed to the public to help them identify two men now considered suspects in the Boston Marathon bombings.
The men were photographed walking down Boylston Street, one behind the other, near the finish line of Monday’s race.
Suspect 1 was seen wearing a light-colored, collarless shirt underneath a dark-colored jacket and wearing a dark baseball cap.
The man identified as Suspect 2 was seen setting down a backpack at the site of the second explosion “within minutes” of the blasts that killed three people and wounded nearly 180, said Special Agent Rick DesLauriers, the head of the FBI’s Boston office. He was wearing a light-colored hooded sweatshirt, a black jacket and a white baseball cap turned backward.
In particular, DesLauriers asked for help from anyone standing in front of the Forum restaurant, where the second bombing happened.