My first novel, Enemies Foreign and Domestic, published in 2003, begins with a sniper shooting into a packed football stadium. Ninety bullets are fired from long range into an upper deck, precipitating a stadium-wide panic stampede that results in over a thousand deaths. In the book, a combat veteran holding a semi-automatic rifle is quickly located by a SWAT counter-sniper in a helicopter, after a citizen’s tip is phoned to the police. However, the veteran is just a patsy, and the true perpetrators of the massacre are a pair of mid-level federal law enforcement agents who are seeking to increase...