Investigators have reportedly found a circuit board that they think triggered the Boston Marathon bombings. These bombs were reportedly made of 6-liter pressure cookers with shards of metals, nails and ball bearings, Fox News and the New York Daily News reported.
The style of bomb, used with rudimentary bomb-making instructions, is the same style frequently used in Afghanistan, Fox News' Jennifer Griffin said.
"The reporting I've received thus far indicates it is that style of explosive device," Texas Representative Michael McCaul said. "That is important for tracing the origins because while it can be made homegrown and can possibly have been, it is the preferred weapon of choice by terrorists in Afghanistan and Pakistan.
There has yet been a terrorist group, domestic or foreign, to claim responsibility for the attacks.
"It's going to be a hard time for the people," journalist Martha Raddatz said, whose experience as a war-time correspondent in the wars of Iraq and Afghanistan gave her a solid understanding of how improvised explosive devices are made. "At least [soldiers] have body armor. In this case, these people were in shorts, flip flops just trying to enjoy the day."
On Tuesday, doctors caring for the over 170 victims of the bombing, reported that they have been pulling nails or nail-like objects from those struck by the two explosions. Dr. George Velmahos, chief of trauma at Massachusetts General Hospital said he believed that the shrapnel specifically came from the bomb, which based on the number of lower extremity injuries, were likely planted low to the ground.
Law enforcement agents revealed that the marathon route had been deemed clear, and swept twice by bomb-detection units before the two bombs went off.
"But people can come and go and bring items in and out," after the races begin, Boston Police Commissioner Ed Davis said.
Officials have also said a larger and long forensic effort is still underway.
"This is the most complex crime scene we've ever dealt with in the history of our department," Davis said, noting that the FBI is leading in the investigation. "Please be patient with us."
Large pieces of metal were seen flying through the air, indicating that the bomb may have been concealed in a mail box or a barrel.
