The Boston Marathon bomber used a pair of six-liter pressure cookers packed with metal nails and ball bearings in hopes of killing as many victims near the finish line during the Boston Marathon, CBS News reported. The placement of both devices in metal pressure cookers could reveal hints as to who was behind the attack, news reports said.
The photograph,obtained by Boston's 7News, which was taken about an hour before the blast, shows one of the hidden bombs had been placed inside a light-colored bag next to what appears to be a mailbox. The follow-up picture taken at the same spot seems to capture the aftermath of the explosion. The second image is blurred because of the of its graphic nature. The lid of a pressure cooker was found on a roof near the scene, a federal enforcement also told CNN.
New York City, too, was on high alert on Tuesday, as 77 suspicious package calls were reported, three times more than normal, even causing one evacuation at LaGuardia Airport's central terminal, news agencies said.
Boston investigators, meanwhile, continue to scour Boylston Street.
"They're picking up every cup, every banana peel. They're looking for nails, marbles, pennies, metal balls - anything that could be a component of a bomb," a Boston police officer said.
On Tuesday, investigators discovered pieces of black nylon bags, and pieces of a circuit board, batteries. Black powder, investigators believe, was the explosive component in the devices, a source said.
Boston police also went door-to-door at stores along Newbury Street collecting surveillance video.
Many of the wounded victims lost arms, legs and other body parts from the explosion, as doctors at Massachusetts General Hospital performed four amputations to patients above their knees.
