UPDATE: 3:28 p.m.
UPDATE: 2:18 p.m.
UPDATE: 2:10 p.m.
From @KTVB on Twitter: "Homeland Security says aspirin was the powdery substance found at the Idaho Statehouse."
UPDATE: 2:03 p.m.
The Idaho Statesman is reporting that Idaho State Police are also investigating a bomb threat that was made about the same time the letter was found this morning. Earlier this week, the Spokesman Review reported that bomb threats had been made involving "either Kootenai County Courthouse or Coeur d'Alene Casino."
UPDATE: 1:54 p.m.
An official statement is expected at 2 p.m. from law enforcement, but Mike Walker with Boise Fire Department says it "looks like substance was benign."
UPDATE: 1:45 p.m.
Police dogs just entered Statehouse. Meanwhile hazmat is finishing up. (via @boiseweekly on Twitter)
UPDATE: 1:32 p.m.
The latest from BW's Twitter feed from our reporters at the Capitol:
"BW at #CapitolEvacuation. Officials said they would have an update in 25 min. That was 40 mins ago. Stay with us pic.twitter.com/0APehxJV"
The Capitol building was evacuated after a white substance was found in a letter to the Attorney General's Office. Hazmat crews emerged from the building and examined something at the staging area set up outside the Capitol doors.
We're told to expect an update any minute form law enforcement. Check back here for details.
Follow @boiseweekly on Twitter for the most up-to-date reporting.