The cyanide in two bottles of Extra-Strength Excedrin that caused the death of two Auburn residents came from the same batch, authorities said after a laboratory test "fingerprinted" samples of the poison.
Susan Hutchcroft of the U.S. Food and Drug Administration said an agency laboratory in Cincinnati analyzed the cyanide linked to the two deaths and also determined that the cyanide is different from that used in past tampering cases, the Seattle Post-Intelligencer reported today.
Each batch's chemical "fingerprint" is unique and can be distinguished from batches of cyanide produced in other parts of the country or even other batches at the same factory, she added, so the FDA may be able to trace the cyanide's batch number.
"We may be able to pin down where this cyanide went to after it was made," she said. But she cautioned that it may be impossible to track down the source of the tampering because of cyanide's easy availability.