SPOKANE -- Authorities from Seattle to Spokane to Boise are actively investigating multiple reports of envelopes filled with an unidentified white powder sent to numerous federal offices across the Pacific Northwest.

Sources confirm that the envelopes were postmarked from Spokane.

Envelopes with an unidentified white powder was sent to at least seven federal offices in Washington and Idaho.

Here in Spokane authorities have confirmed that an envelope with a white powder substance was found in one of the FBI’s local offices. Local officials also confirm an envelope with white powder was delivered to one of the offices at the federal building located at 6450 Mineral Drive in Coeur d'Alene. FBI spokeswoman Debbie Dujanovic Bertram in Salt Lake City, Utah, said similar letters had been found at the U.S. attorney's office and the FBI office in Coeur d'Alene.

In Western Washington, white powder was found in an envelope sent to the IRS office in Bellevue. The office, located at 520 112th Ave.NE, was evacuated after the envelope was found at 12:27 p.m. One person was in the room at the time the envelope was opened and some white powder fell out; that person didn't report any ill effects.

About 11 minutes later at 12:38 white powder was found in an envelope delivered to the federal courthouse in downtown Seattle. Two people were in the room at the time the envelope was opened; they were isolated but were not showing any ill effects.

In Boise the US Attorney’s Office was evacuated after a white powder was discovered in an envelope mailed to that office. FBI spokeswoman Debbie Dujanovic Bertram also said that an envelope with white powder inside was sent to the FBI office in Pocatello.

Late in the afternoon Monday the FBI confirmed that some of the white powder was also mailed to the FBI field office in Salt Lake City.

Bertram said field tests indicated the substances were not toxic, but samples were sent back to labs for further testing.