article_snippet: Wednesday morning from an FBI agent who led the agency's efforts .
article_snippet: to recover evidence from the debris-strewn blast sites.
article_snippet: Other FBI agents on Tuesday described how some 3,000 pieces of evidence, including shrapnel and body parts, were retrieved from the blast sites near the marathon finish line, some on surrounding rooftops as high as four stories.
article_snippet: an FBI agent who led the agency's efforts also told the court that investigators found shrapnel along with ball bearings, a zipper, shards of metal, small nails and duct tape in the aftermath.
article_snippet: Prosecutors resumed questioning an FBI agent who led the agency's efforts on Wednesday, the . fifth day of the long awaited Boston bomber trial.
article_snippet: Some 3,000 pieces of evidence, including shrapnel and body parts, were retrieved from the blast sites near the marathon finish linethe marathon finish line, some on surrounding rooftops as high as four stories .