A woman who works at the National Institutes of Health in Rockville, Maryland, was arrested in Maryland on Monday, after making a threat to infect Florida property assessors with anthrax for revoking her tax exemption.
The U.S. Attorney's office says Michelle Ledgister, a federal health agency worker was charged with making a false threat, under an anti-terrorism law enacted last year.
The law makes it a federal crime to convey false information about anthrax exposure, and is punishable by up to five years imprisonment.
In 2001 anonymous anthrax attacks caused panic after the Sept. 11 attacks, when they killed five people and sickened 17 others in the United States.
The first poisoning was in South Florida, where a tabloid photo editor died after apparently receiving anthrax in the mail.
As yet no one has been charged in those cases.
According to investigators, Ledgister, 43, left a phone message at the Broward County Property Appraiser's office in Fort Lauderdale, Florida, after it revoked a homestead exemption on property she owned in Florida, which increased her tax bill by $2,300 a year.
The arrest warrant quoted her as saying on the tape, "You guys now have anthrax spores once again, so do be careful".
When hazardous materials teams searched the appraiser's office no anthrax was found.
An FBI spokeswoman says that in her role as an analyst with the NIH Institute of Allergy and Infection Disease in Maryland, Ledgister had no access to anthrax.