In the third season, the relationship between Nick's partner Det. Tracy Vetter and her father became an ongoing minor subplot in the series, usually treated as a running gag. Tracy's father, Richard Vetter, is a former senior police officer who is now on the Police Commission. During the course of his career, he saw nothing wrong in bending rules to achieve his goals. This involved closing cases, covering for colleagues, and furthering the careers of those who were his protegés, such as Bruce Spencer. His attitude hasn't changed with his promotion to Commissioner. And no one's career matters more to him than that of his daughter Tracy.