FBI and postal inspectors investigate powdery mail sent to election offices across multiple states ahead of Nov. 3 midterms, prompting evacuations and heightened security

The FBI and postal inspectors are investigating suspicious mailings containing an unknown powdery substance that were sent to election offices in multiple U.S. states ahead of the Nov. 3 midterms. The incidents have prompted authorities to heighten security and report evacuations.

Envelopes containing the substance triggered an evacuation in Oklahoma and were intercepted in Ohio. Authorities are investigating who sent the packages.