Further tests did not confirm the presence of the spores, most probably they had perished during their irradiation with special equipment.
Nevertheless, the Pentagon's representatives sent some samples to Fort Dietrich (State of Maryland), where the National Research Center for Infectious Diseases is located, for confirmation or otherwise of the spores having been present in the mail of the US DoD. The experts expect to get exact data within 2-3 days.
The mailing office of the US Defense Department is equipped with devices that expose the incoming mail to radioactive treatment to destroy any possible infection. The Pentagon's both post offices employ 175 and 100 people respectively.
This is not for the first time that Washington has been targeted for bacteriological weapon attack. Soon after the attacks of September 11, 2001, envelopes with anthrax spores were received at the offices of US senators Tom Deshl (South Dakota) and Patrick Leahy (Vermont), as well as at the representative offices of national TV companies in New York. Then 5 people died of anthrax.