In the years since, much has come to light about this pivotal event in the history of U.S. interventions in Central America. But the full story of how one of the most junior officers in the U.S. embassy in San Salvador tracked down the killers has never been told. It is the tale of an improbable bond between a Salvadoran soldier with a guilty conscience and a young American diplomat with a moral conscience. Different as they were, both men shared a willingness to risk their lives in the name of justice.It's well worth a read.
Raymond Bonner has a terrific article in ProPublica on The Diplomat and the Killer (h/t Sonja Wolf). In it, he tells the story of how a US foreign service officer and a Salvadoran soldier cracked the wall of impunity behind the murders of the four US Churchwomen in December 1980.