Wrongly convicted prisoners aren't just all profoundly unlucky—most of them cracked at some point during the long ordeals of investigation and interrogation. John Grisham's first non-fiction book, The Innocent Man, primarily concerns Ron Williamson and Dennis Fritz, who were sent to prison in 1988 for the rape and murder of an Oklahoma woman, then freed thanks to new DNA evidence in 1999. But one of the book's more compelling subplots involves a contemporaneous case in the same small town. Two other men, Tommy Ward and Karl Fontenot, exhausted by police grilling, confessed to a murder they didn't commit, figuring that a lack of evidence would free them. Instead, the confessions held up in court; emboldened by their success, the police and prosecutors tried to force Williamson and Fritz to break down, too. When they wouldn't, the prosecution pressured some jailhouse snitches into making up confessions for them—and again, those "confessions" held up in court.
Grisham takes a bare-bones approach to The Innocent Man, laying out the facts of the cases in simple declarative sentences. But a third of the way into the book, even Grisham has had it. Initially, he just sneaks in the occasional snide comment about corruption and injustice in rural Oklahoma. But by the end of The Innocent Man, he's openly railing against the stupidity and laziness of local law enforcement. Rather than exposing the inherent flaws in capital punishment, Grisham fumes about how our whole legal system is based on the lie of "innocent until proven guilty."
Frankly, Grisham overdoes it a little. He states and re-states each malfeasance, and writes in exhausting detail about Williamson's untreated mental illness. But when Grisham gets into what happened to Williamson and company during their prison stay, The Innocent Man finds its purpose. In describing the wretched food, poor ventilation, and abusive guards—all factors that led to Oklahoma prisons being condemned by Amnesty International—Grisham makes clear exactly what's at stake when the state sends the wrong man to jail. The book is ultimately about the invisible switch that gets pulled once a case shrouded in doubt is decided in favor of the prosecution, and suddenly even the shakiest evidence becomes "overwhelming" and "incontrovertible," and the new prisoners disappear down a dark, hollow hole.