High profile Harvard Law School professor Alan Dershowitz received an envelope laden with white powder, after a number of similar letters were sent to a New York newspaper earlier this week, the Federal Bureau of Investigation said Thursday, according to dpa. All the letters were postmarked from Knoxville, Tennessee, the FBI said in an e-mailed statement. The case is being handled by the Knoxville FBI Joint Terrorism Task Force. At The Wall Street Journal, the discovery prompted the evacuation Wednesday of one floor used by both executives and editorial page staff, and all Journal employees were sent an email warning them not to open any post.