Chief Security Officer
The Chief Security Officer is called Chief of Security. Her/his duty is to ensure the safety of ship and crew. Some take it as their personal duty to protect the Commanding Officer/Executive Officer on away teams. She/he is also responsible for people under arrest and the safety of guests, liked or not. S/he also is a department head and a member of the senior staff, responsible for all the crew members in her/his department and duty rosters. Security could be called the 24th century police force.