On a scorching September 2007 Baghdad afternoon, a 19-man convoy of four armored Blackwater trucks rolled into Nisour Square, one of the city’s most congested and volatile intersections. What happened next would ignite an international firestorm, trigger a yearslong legal battle and leave four American contractors known by their team’s call sign, Raven 23, branded war criminals. It became “one of the most notorious incidents of the Iraq War,” writes Gina Keating in her new book, “Raven 23: How the Department of Justice Betrayed American Heroes.” Yet “nearly every ‘fact’ in the official story was a lie.”