[link to articles.courant.com]

An Elementary school in Hartford, Conneticut got a white envelope... but this article goes on to say that back in FEBRUARY there were even more envelopes being sent out from OREGON (not Dallas as the current ones are).

On Feb. 23, U.S. Sen. Joseph Lieberman's office in Hartford received an envelope containing white powder. Authorities said a number of state offices of U.S. lawmakers, as well as media organizations and offices for TV shows, had received similar letters, all postmarked from Oregon.