At issue in this appeal is the admission of two documents: the official report of the Customs Service chemist who analyzed the substance seized from Daniels' (D) person, and its accompanying worksheet. Weinberg, the chemist who prepared the reports, was ill and unable to testify at trial: the government had intended to call Weinberg to testify that the substance he had analyzed was heroin. Instead, the government called Harrington, another customs service chemist. Although Harrington did not know Weinberg personally, she was able to testify to the regular practices used by the customs Service chemists to identify unknown substances. When D objected to the introduction of the reports through Harrington, the government relied on the modified business records exception found in Rule 803(6).