Contrary to some media speculation, top military leadership knew as early as late 2009 that Army Sgt. Bowe Bergdahl had deserted. During an open-book question and answer session in Afghanistan, members of Bergdahl’s platoon directly asked then-Chairman of the Joint Chiefs Admiral Mike Mullen whether he was aware of Bergdahl’s desertion. Mullen “told me that he knew of the circumstances surrounding his walking off,” former Sgt. Matt Vierkant, one of the platoon members, told Fox News, and “that they were developing leads and following leads, trying to do everything they could to get him back.” Evan Buetow and Cody Full,...