SEATTLE (AP) -- U.S. Sen. Patty Murray's downtown Seattle office is among a handful of congressional offices that received threatening letters containing a suspicious powdery substance that proved harmless.
The FBI and the U.S. Senate's top law enforcement officer discussed the letters Wednesday.
Sergeant-at-Arms Terrance Gainer said in a memo to Senate offices that the letters were sent to several state and home district offices.
KOMO-TV reports that Murray spokesman Matt McAlvanah confirmed a similar letter was sent to the Democrat's offices in Seattle's Federal Building. Hazmat crews responded Wednesday afternoon and determined the substance was harmless.
The spokesman says Murray was not in the office when the letter was discovered.
FBI spokesman Peter Donald said letters were also set to several media organizations.
The letters tell the recipients there is a "10 percent chance you have just been exposed to a lethal pathogen."
The letters were postmarked Portland, Ore., but the Portland return address appears to be phony.