At least one was a pressure cooker that contained BBs and nails, the affidavit said.

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The device also had fragments that may have included nails, BBs and ball bearings, the agency said.

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"They look like BBs, " he said, adding that the balls were distinct from the shrapnel thrown up from debris on the street.

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Park learned to program motion-graphics synchronized to dance music and ran a BBS, an electronic bulletin board system, the precursor to the Internet.

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Being able to access the internet from home -- again, that old Atari had seen some BBS action in its day -- changed everything.

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The Federal Bureau of Investigation already has described other parts of the bombs, which were placed in pressure cookers and packed with nails and BBs.

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The FBI said late Tuesday that what appeared to be fragments of ball bearings, or BBs, and nails had been recovered and had possibly been contained in a pressure cooker.

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Among the shrapnel that struck victims were BBs.

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