A U.S. Army reserve agent practices clearing a corner as part of responding to an active shooter training during Guardian Shield, 1 Aug., 2016. Agents from Criminal Investigation Commands across the United States, belonging to the 200th Military Police Command, gathered in Charleston, South Carolina, July 24 to Aug. 5, for Guardian Shield, 2016. Guardian Shield is a two-week training that certifies agents in various courses such as crime and intelligence analysis, drug suppression and domestic violence intervention.