The Washington Post is reporting that NPR headquarters today (Oct. 26) received a bomb threat in the mail. NPR sources told the paper that the letter was turned over to local police and the FBI. NPR did not publicly disclose details of the threat on the advice of law enforcement, the paper said. The letter didn’t specifically reference the controversial firing of correspondent Juan Williams on Oct. 20, but NPR sources said the timing and tone suggested it was sent after his termination. NPR warned its employees Monday (Oct. 25) about a “security threat” in a staff memo, but did not provide specifics.