Authorities from the FBI, Secret Service and The Office of Hazardous Materials Safety investigated three separate suspicious packages found in government buildings Thursday, according to 2NEWS affiliate KFOR in Oklahoma City.
Investigators were first called to the U.S. Attorney's Office in downtown OKC over a letter containing an unknown white powder, according to the outlet.
KFOR is reporting another letter or possible package was found at the Federal Courthouse with the same white powder, and another at FBI headquarters.
Authorities are trying to confirm who sent the packages and if they're related. Authorities have also not released the make up of the powder, but, according to KFOR, have ruled out anthrax.