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Last Updated

27 Feb 2003

Source: Washington Post, June 23, 2002.

Anthrax Spores From Hill Said to Be Made Recently

Officials Say Finding Suggests Attacker Had Access to Modern Lab and Could Make New Batch

By Guy Gugliotta, Washington Post Staff Writer

Government officials said yesterday that scientists have determined that anthrax spores mailed to Capitol Hill last fall were made less than two years ago, suggesting that the author of the anthrax attacks had access to a modern laboratory and could make a new batch of the lethal pathogens.

The officials said the researchers' new determination did not change the general direction of the FBI investigation, which for months has been searching for a suspect among disgruntled domestic scientists with the expertise needed to culture, mill and "weaponize" the spores.

But the new findings cast further doubt on the hypothesis that the spores could have been stolen from a lab decades ago, saved in dry storage and used in the wave of attacks last October and November.

FBI Director Robert S. Mueller III, at a recent meeting with Washington Post editors, declined to discuss the eight-month investigation in any detail. The new findings do not appear to have pushed the investigation appreciably forward.

The bureau has acknowledged it has no suspects in the case, nor has it identified a source for the spores that infected 18 people and killed five in the worst outbreak of biological terrorism in U.S. history.

Investigators found several letters that contained anthrax spores and suspect others went undiscovered. Most of the ongoing laboratory work, however, uses spores from a letter sent to Sen. Patrick J. Leahy (D-Vt.), found intact in a barrel of unopened mail in November. It is the only anthrax letter that still contained a significant amount of powder by the time investigators took control of it.

Anthrax is a common livestock disease caused by a bacterium that can lie dormant for years in dried spore form. "The secret of spore longevity is to package it in the absence of humidity," said Bill Patrick, a former chief of product development in the offensive biological weapons program that the United States abandoned in the early 1970s.

"When the agents pick up moisture, the particle size grows, the powder deteriorates and the agent loses the qualities that make it a potent weapon," Patrick said. But if the spores are kept dry, they are remarkably resilient.

Figuring out the age of anthrax spores, however, can be difficult. One source said that under a microscope older spores tend to look "wrinkled," but the same effect could be achieved by varying the drying methods to make newer spores look old.

Instead, investigators until recently focused on determining the rate of genetic mutation across generations of bacteria, hoping to backtrack the spores used in the attacks last year to their lab of origin.

Several sources said that this method is not producing results because the genetic variations may not be dramatic enough. Anthrax expert Martin E. Hugh-Jones of Louisiana State University said he had the feeling that the investigation was "grounded."

The new findings on the relative youth of the Leahy spores were first reported yesterday on the New York Times Web site, which suggested that the dating had been done with radiocarbon analysis, a technique more commonly used by archaeologists to determine the age of artifacts tens of thousands of years old.

Biologist Jennie Hunter-Cevera, president of the University of Maryland's Biotechnology Institute, said analysts didn't necessarily have to use radiocarbon dating, which determines the age of an object by the rate at which the radioactive carbon 14 isotope decays in organic materials.

Instead, Hunter-Cevera said "isotopic" analysis could compare the radioactivity ratios from the isotopes of several elements to get an age. Carbon 14 dating is sometimes suspect for recent objects because the atomic testing of the 1950s created higher levels of carbon 14 in the air while increased use of fossil fuels has enriched the air with more inert carbon.

The exact scientific process the FBI has used with the Leahy letter has been kept secret, Hunter-Cevera said, but among microbiologists the news that this technique was bearing fruit began to leak out several weeks ago.

"The FBI appears to be getting good scientific advice," she said.

Staff writer Joby Warrick contributed to this report.