On Aug. 20, 2013, bookkeeper Antoinette Tuff (right) calmly talked a gunman into surrendering at Ronald E. McNair Discovery Learning Center in DeKalb County. Her actions led to the surrender of Michael Brandon Hill, who had entered the front office of the learning center during school with a rifle and nearly 500 rounds of ammunition. KENT D. JOHNSON / KDJOHNSON@AJC.COM