FBI Special Agent Richard DesLauriers
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Boston Marathon bombing: FBI reveals pressure cooker clues

Bombs that targeted the Boston Marathon on Monday may have been packed in pressure cookers, investigators have said.

FBI Special Agent Richard DesLauriers told a news conference that pieces of nylon had been recovered from the scene, along with fragments of ball bearings and nails that were "possibly contained in a pressure-cooker device.''

He said they were being sent to the agency's laboratory in Quantico, Virginia, where experts would reconstruct the devices to determine their make-up and components.

Three people were killed and more than 170 injured when two bombs exploded near the finish line of Monday's race.

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