Letters containing a powdery substance were mailed to at least 30 state Governors in December. The letters surfaced in Alabama, Alaska, Arizona, Colorado, Connecticut, Florida, Georgia, Hawaii, Idaho, Indiana, Iowa, Kansas, Maine, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, North Carolina, North Dakota, Oklahoma, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, West Virginia and Wyoming, plus Puerto Rico and the Virgin Islands. Preliminary tests found the powder to be not biological or toxic, and no injuries have been reported.

Officials suspect there may be more letters that have yet to be discovered. The substance was contained in business envelopes postmarked Dallas, Texas, with no return address.

Evacuations were ordered in many of the gubernatorial offices and government operations were disrupted. In New Mexico more than 30 people were quarantined and decontaminated with a solution containing bleach.

The penalty for sending hoax letters is up to five years in prison. The FBI is working with law enforcement agencies in each state to investigate. An FBI spokeswoman in Washington referred questions about the investigation to the bureau's offices in each state. There was no information on whether the letters contained any political message.