Arizona Republican gubernatorial candidate Kari Lake’s campaign office is shut down Sunday, as police investigate a staffer allegedly being exposed to white powder from an envelope mailed to the office.

The staffer opened the envelope containing the substance. Shortly thereafter, law enforcement ranging from Phoenix police to the Federal Bureau of Investigation, including HAZMAT crews and bomb squad, arrived at the scene.

The staffer has not yet reported any symptoms after the incident overnight, according to NBC News correspondent Vaughn Hillyard. But the campaign said in a statement that they are under ‘medical supervision, and that they are “taking this security threat incredibly seriously.”

We're told a Lake campaign staffer opened one of the envelopes & was exposed to the material — this individual has not reported any symptoms/injuries.

The Phoenix Police confirm that law enforcement seized items of this location. https://t.co/fk1MCQoHek

— Vaughn Hillyard (@VaughnHillyard) November 6, 2022

“In the meantime, know that our resolve has never been higher and we cannot be intimidated. We continue to push full speed ahead to win this election on Tuesday,” a campaign spokesperson said in a statement.

The campaign added that they are “awaiting details,” and that there was reportedly a second envelope being investigated, as well.

The Kari Lake campaign has provided me this statement on the suspicious package situation.

The staffer is under medical supervision. pic.twitter.com/sON8OAS4Tn

— Cameron Arcand (@cameron_arcand) November 6, 2022

Lake is currently in a competitive race against Democrat Katie Hobbs, who is the incumbent Arizona secretary of state.

As this is a breaking story, RedState will provide more details as they become available.