Gail Duvall was a lieutenant with the Open-Unsolved Unit of the Los Angeles Police Department's Robbery-Homicide Division. In that capacity she supervised Harry Bosch, David Chu, Tim Marcia, and others. She is mildly paranoid and agoraphobic which diminishes her effectiveness as a supervisor. Her office window faces the LA Times building, so she has her window completely covered to prevent any reporters from seeing anything in her office. She also has windows facing into the squad room, but she keeps her blinds closed most of the time, giving the impression that she works in a cave. She is not a "street" detective, preferring to stay in her office while her subordinates handle everything. On Monday 10 October 2011 when Bosch and Chu arrested Chilton Hardy, command staff sent Larry Gandle rather than Duvall to oversee the investigation.