FBI agents have arrested a Denver man accused of sending intimidating letters containing a non-poisonous white powder to several government offices, including those of U.S. Senators Mark Udall and Michael Bennet and the offices of U.S. Representatives Mike Coffman and Diana DeGette. 9News [2] reports that Jay DeVaughn, a reportedly exemplary college librarian, so far faces a federal charge of mailing threatening communications. DeVaughn has been the director of library services at the Community College of Aurora, according to The Denver Post [3], and "was clean" after a background check before he got the job two-and-a-half years ago, says the college president. An affidavit notes that FBI agents believe DeVaughn put four suspicious letters into a drive-through drop box at the Wellshire Post Office at 2080 S. Holly St. on February 22 (via 7News [4]). Those letters were addressed to an Argentine Embassy and included plastic sandwich bags containing a "white powdery substance and a single sheet of paper," according to the arrest affidavit. The paper contained more than 200 black-and-white photos of men and women. "Por los Desparecidos" [sic]---roughly, "For those who have disappeared"---was written at the bottom of the paper. DeVaughn, agents say, could perhaps be linked to other recent white powder incidents.