Special Agent Frederick Gutt says the letters were found at a federal building in Seattle, Internal Revenue Service offices in Bellevue, Wash.; and an FBI office in Spokane, Wash.
In Idaho, FBI spokeswoman Debbie Dujanovic Bertram says envelopes with powder were found in the U.S. Attorney's office and an FBI office in Coeur d'Alene, an FBI office in Pocatello and the U.S. Attorney's office in Boise.
Bertram says the FBI office in Salt Lake City also received a letter with a substance.
Gutt says the FBI has collected the substances for testing. Bertram says field tests in Idaho indicated the substances weren't hazardous.
