The FBI says an inmate from the Oklahoma State Penitentiary in McAlester sent what he claimed were anthrax-laden letters to federal and state offices in Oklahoma, as well as to the U.S. Court of Appeals in Washington D.C.
The United States Attorney's Office for the Eastern District of Oklahoma received the first suspicious letter on Wednesday. It was from an Oklahoma prison inmate who claimed the white powder in the letter was anthrax.
The FBI interviewed the prison inmate and learned he sent similar letters to the Oklahoma City offices of the FBI, the Oklahoma State Attorney General, and the U.S. Attorney. All three of those letters were found on Thursday, and they all contained a white, powdery substance.
Agents from both the FBI and Secret Service, along with Oklahoma City police, Oklahoma County sheriff's deputies and hazardous materials crews, responded to all three scenes and removed the letters.
Initial field tests and preliminary lab tests indicated the white powder was not anthrax.
The letter sent to the U.S. Court of Appeals in Washington DC was intercepted Friday by the U.S. Postal Inspector's Office.
The FBI has not released the suspect's name.