Lt. Col. Mario Diaz, a native of Sierra Madre, California, shakes hands with one of 17 former prisoners who were released at a ceremony at the Nassir Wa Salam Iraqi police station, April 17. Each man signed an oath promising to help maintain peace. Diaz is the commander of 1st Battalion, 21st Infantry Regiment "Gimlets," 2nd Stryker Cavalry Regiment, Multi-National Division – Baghdad. (U.S. Army photo/Spc Dustin Weidman, 21st Infantry Regiment, 2nd Stryker Cavalry Regiment)