William Arnold Jefferson (November 28, 1951 – November 19, 1995) was an American librarian and United Nations employee who was killed while serving in Bosnia and Herzegovina.Jefferson was found shot to death near Banovići, Bosnia and Herzegovina.His killing was originally described as a criminal act, connected with robbing him of his valuables. American counter-terrorism officials were later to imply it was an act of terrorism. Jefferson was a Librarian at the U.N., who volunteered take leave to serve in Bosnia.