PHOTOS: Explosions Rock Boston Marathon

(NEWSER) – The FBI has released images of the remains of a "pressure cooker" bomb used in the Boston marathon attack and the backpack it was hidden inside, ABC reports. The second bomb was also hidden in a backpack, but it's not clear whether it was also made from a pressure cooker, the FBI says. Investigators say the bombs—packed with BBs, nails and pellets to maximize shrapnel injuries—may have cost less than $100 to build and were made from ingredients so ordinary that tracing them may be impossible, reports the Washington Post.

Click here to see more photos of the bombs from KFI

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