The Citadel has dismissed a cadet for one academic year and suspended two others for a semester for their role in an incident in which several cadets at the South Carolina school donned white pillowcases for a costumed event that many saw as evocative of the Ku Klux Klan. The punishment, reported Monday by the Post and Courier, concluded an investigation that began after the Dec. 9 incident was reported to the administration of the public military college. Images of white-hooded cadets circulated at the time on social media.