This was not much reported, but a letter bomb was discovered at the Fourth Circuit courthouse in Richmond earlier this week. A source told me that initial indications were that the bomb would have exploded had it not been discovered by the Marshals Service. Later in the week, during an en banc hearing, Chief Judge Wilkins announced that the courthouse had been sealed because of another letter bomb which appeared to contain anthrax. It was later discovered that the "anthrax" was body powder.
My source also indicated that the "anthrax letter" originated from a federal prison.
A news story on the first bomb can be found here.