Only five days before a car bomb planted by agents of the Pinochet regime rocked downtown Washington D.C. on September 21, 1976, [assassinating Chilean exile diplomat Orlando Letelier and his assistant Ronni Moffitt,] Secretary of State Henry Kissinger rescinded instructions sent to, but never implemented by, U.S. ambassadors in the Southern Cone to warn military leaders there against orchestrating a series of international murders," declassified documents obtained and posted by the National Security Archive revealed today. The instructions effectively ended efforts by senior State Department officials to deliver a diplomatic demarche, approved by Kissinger only three weeks earlier, to express "our deep concern" over "plans for the assassination of subversives, politicians, and prominent figures both within the national borders of certain Southern Cone countries and abroad." "The September 16th cable is the missing piece of the historical puzzle on Kissinger's role in the action, and inaction, of the U.S. government after learning of Condor assassination plots," according to Peter Kornbluh, the Archive's senior analyst on Chile and author of the book, The Pinochet File: A Declassified Dossier on Atrocity and Accountability. "We know now what happened: The State Department initiated a timely effort to thwart a 'Murder Inc' in the Southern Cone, and Kissinger, without explanation, aborted it," Kornbluh said.