Secretary Gates and Gen. George Casey Jr. lead applause for Sheila Casey. Secretary of Defense Robert M. Gates (left) and Chief of Staff of the Army Gen. George Casey Jr. lead applause to recognize the service of Sheila Casey during a retirement ceremony in the Pentagon on Apr. 11, 2011. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 931667-J-IXZ90-769.jpg Photo Gallery