Senior Airman Zachary Fredrick, 5th Security Forces Squadron military working dog handler, and 5-year-old German Shepherd Roko compete in the 2013 North Dakota Peace Officer Association K-9 Police Trials at Minot Air Force Base, N.D., Aug. 14, 2013. The trials included narcotics and explosive search competitions, as well as the Iron Dog event, which tested both handlers and dogs physically and mentally. (U.S. Air Force photo/Senior Airman Brittany Y. Auld)