State officials say a "suspicious letter" that caused an evacuation at Gov. Pat Quinn's constituent services office in Springfield contained baby powder.
Gov. Pat Quinn spokesman Grant Klinzman says everyone returned to the office Tuesday afternoon.
About a half dozen people were evacuated from the office's mail room when the letter was found. The office is across the street from the state Capitol where lawmakers were gathered to take a vote on pensions.
Springfield Fire Chief Ken Fustin says the investigation began when the content of the letter and substance were determined to be a "legitimate threat" that prompted further investigation.
Earlier in the day, fire trucks waited outside the offices as employees gathered in a stairwell and near the entrance waiting for the all-clear to return.