Despite the subtitle, this book is not about chasing down an al-Qaeda killer. Instead, it is about chasing the evidence necessary to convict one in a U.S. criminal court. In 2011, Ibrahim Harun, an al-Qaeda agent who killed American troops in Afghanistan, introduced himself to Italian police on a ship carrying people escaping Libya. The Italians were keen to hand Harun over to the Americans, but they did not want him to enter military custody, so the United States was forced to try him in a