** FILE ** Police officers run from Norris Hall on the Virginia Tech campus in Blacksburg, Va., on April 16, 2007, after the worst mass shooting in modern U.S. history. (AP Photo)

Photo by: Matt Gentry

** FILE ** Police officers run from Norris Hall on the Virginia Tech campus in Blacksburg, Va., on April 16, 2007, after the worst mass shooting in modern U.S. history. (AP Photo)