TAMPA (CBSMiami/AP) – A former Polk County teacher is accused of mailing threatening letters containing white powder to several elementary schools where she once worked.

The FBI arrested Maria Bassi Lauro, 65, at her Davenport home on Wednesday. She made her initial appearance in Tampa federal court on charges of mailing threatening communications and transmitting false information and hoaxes.

An indictment says Lauro sent the letters to three elementary schools in Polk and Lake counties between August and September last year. The recipients believed that the powder could be harmful because anthrax, ricin and other toxins can appear as a white powder.

Later analysis determined the powder was harmless. The indictment didn’t suggest a motive for the threats.

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