Powder Used in Anthrax Attacks 'Was Not Routine'
By Joby Warrick
Washington Post Staff Writer
Tuesday, April 9, 2002; Page A09

Whoever concocted the wispy white powder used in last fall's anthrax attacks followed a recipe markedly different from the ones commonly used by scientists in the United States or any other country known to have biological weapons, law enforcement sources said yesterday.

Extensive lab tests of the anthrax powder have revealed new details about how the powder was made, including the identity of a chemical used to coat the trillions of microscopic spores to keep them from clumping together. Sources close to the investigation declined to name the chemical but said its presence was something of a surprise.

The powder's formulation "was not routine," said one law enforcement official, who spoke on the condition of anonymity. "Somebody had to have special knowledge and experience to do this," the official said.

The finding, one of several emerging from months of intensive laboratory analyses of anthrax spores mailed to Senate offices in October, appears to further deepen the mystery of who is behind the worst act of biological terrorism in U.S. history.

The FBI has long suspected the attack was the work of a domestic scientist -- possibly someone formerly associated withh the U.S. biological defense program or one of its contractors. But the discovery of the chemical suggests the culprit did not merely ape techniques developed by U.S. defense scientists -- or, for that matter, those used in other countries with known biological weapons programs, such as the former Soviet Union or Iraq.

The Bush administration had previously disclosed that the anthrax powder contained silica -- a chemical known to have been used in the U.S. germ warfare program in the 1950s and 1960s -- but not bentonite, an additive in some Iraqi biological weapons.

Some details of the new findings were reported by Newsweek in its April 8 edition.

The FBI has informally briefed top Bush administration officials about the new findings, though law enforcement officials yesterday insisted they have not significantly changed their hypothetical profile of the person behind the attack.

The agency continues to believe, based on the balance of evidence, that the culprit is a U.S. scientist with highly specialized training and skills, the sources said.

"If anything, this has narrowed our focus," one law enforcement official said.

The FBI is pursuing its forensic investigation along several parallel tracks, examining not only the chemical and physical makeup of the powder but also looking at genetic signatures that may pinpoint the lab where the bacteria originated.

The anthrax-by-mail attacks in September and October killed five people and sickened at least 13 others in the first fatal instance of biological terrorism on U.S. soil.