Senior law enforcement sources tell ABCNEWS a powdery anthrax-contaminated substance discovered on Capitol Hill is extremely fine, highly concentrated and "definitely not the work of an amateur."
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Authorities confirmed publicly today that the white powder contained in a letter received a day earlier by Senate Majority Leader Tom Daschle's office on Capitol Hill tested positive for anthrax spores.
Senior law enforcement officials tell ABCNEWS the substance appears to have been designed and milled specifically to stay in the air, requiring special machinery, and leading to a greater chance infecting people with the more deadly inhalation form of anthrax. The sources also said the powder was highly concentrated with anthrax spores.
Both of those qualities are characteristic of military-grade material, suggesting the substance was produced by a well-funded, highly sophisticated and possibly state-funded operation.
"These are no amateurs," said one official.
And lawmakers say they have been advised that the anthrax-laden powder appears to have been "produced by a sophisticated organization."
Authorities say there is a long list of countries that have produced such weapons-grade anthrax, ranging from Iraq and Russia to Britain and the United States.
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The substance tested positive for anthrax in two preliminary field tests and Capitol Police were notified Monday night that a more exhaustive test at the Fort Detrick Army research facility in Maryland had confirmed the presence of anthrax spores.
"Now we know that we're dealing with an actual anthrax situation," Capitol Police spokesman Lt. Dan Nichols said this morning.
The section of the Hart building where Daschle's personal office is located was temporarily shut down as a precaution and the ventilation system was being checked for spores.
Mail delivery to Capitol Hill also was being suspended for a second straight day as authorities put new, more rigorous screening procedures in place. Public tours of the Capitol have also been suspended.
No one on Capitol Hill has been diagnosed with the disease or with anthrax exposure, but some 40 to 50 people — including members of Daschle's staff and others who may have come in contact with the letter — were being tested and treated with antibiotics. Daschle himself never had contact with the letter.
"We simply know that we have a positive substance," said Dr. John Eisold, the attending physician for the Capitol.
• Daschle, Brokaw Letters Believed Linked
Federal authorities said today they are investigating similarities between a letter containing anthrax that was delivered to Senate Majority Leader Tom Daschle's office on Capitol Hill and another sent to NBC News anchor Tom Brokaw's office in New York.
FBI Director Robert Mueller told reporters at the Justice Department today that the similarities were in handwriting on the two letters.
A federal official who has seen both letters said they were both dated "09-11-01," the date of the terrorist attacks in New York and Washington, and contained the same message: "This is next. Take your medicine. Death to America."
The letter to Daschle also added: "Death to Israel. Allah is great."