Arizona Gov. Jan Brewer (R) Tuesday received an envelope packed with a "white powdery substance," which was opened by an employee at the state capitol.

The Arizona Republic reported that the envelope caused a one-hour lock-down at the capitol in Phoenix. No illnesses or injuries have been reported, and the complex was reopened just after 11 a.m. local time.

The scare came weeks after Brewer signed a controversial law that requires that, under certain circumstances, state and local law enforcement check the identification of people they suspect are in the country illegally.

Almost two weeks ago, staff in the district office of Rep. Raul Grijalva (D-Ariz.), an opponent of the law, received death threats. A staffer in Rep. Trent Franks' (R-Ariz.), who supports the law, also received a threat.

The Federal Bureau of Investigation (FBI) is assisting local law enforcement with the investigation into the envelope sent to the governor's office.