The Federal Bureau of Investigation have linked a letter with a white powdery substance inside to a Oklahoma state prison inmate.
According to a release from the FBI, the United States Attorney's Office for the Eastern District of Oklahoma received a letter containing what a prison inmate claimed to be anthrax, Wednesday, March 13.
Agents interviewed the prison inmate and learned similar letters were sent to the U.S. Attorney's Office, FBI and Oklahoma State Attorney Generals' Office in Oklahoma City. The offices received the letters on Thursday.
A letter intended for the U.S. Court of Appeals, Washington D.C. was intercepted by the U.S. Postal Inspector's Office today, March 15. It was also determined that a letter received by the U.S. District Court on Thursday was determined to be a complaint.
The field screening and preliminary lab test were negative for the letters containing the white powder.