2012/09/12 Headlines: U.S. Ambassador, 3 Staffers Killed in Libya in Outburst over Anti-Muslim Film; U.S. Denies Obama Snub as Netanyahu Escalates Iran Threats; U.N. Envoy to Meet Assad, Rebels in Syria; Dead Gitmo Prisoner Had Been Cleared for Release, Attempted Suicide; U.S. Marks 11th Anniversary of 9/11 Attacks; Chile Commemorates U.S.-Backed 1973 Coup; Chicago Teachers' Strike Enters 3rd Day; UBS Whistleblower Rewarded $104 Million by <span class="caps">IRS; 5 More Suspects Indicted in Georgia Militia Plot; Shell Faces Protests, Delays as Arctic Drilling Begins; Mexican Peace Caravan Wraps Up in D.C.;$