Ernest Hemingway famously said that "the most essential gift for a good writer is a built-in, shock-proof shit detector. This is the writer's radar and all great writers have had it." He was talking about the novelist, I suppose. But his dictum applies to the investigative journalist, in spades. It is the born reporter who insistently, even masochistically, clings to the notion that things are not what they outwardly seem and pursues the hidden truth in any situation even when other people prefer to ignore it. For most people this simply is not normal human activity.
Imagine discovering that a paid FBI informant may have actually killed a civil rights worker during one of the most famous civil rights marches in U.S. history? Or that a top county public school official had put 23 of his relatives on the payroll, sexually harassed female employees and separately had informed the parents of handicapped students that their children couldn't attend school.