Cassie Maddox is a fictional character from the novel series written by author Tana French. She works as a detective in the Dublin Murder Squad, a fictional police unit in Ireland. Cassie is known for her keen investigative skills and her ability to connect with people, which helps her solve complex cases. In addition to her role as a detective, Cassie has a unique background in undercover work. This experience allows her to adopt different identities, which plays a significant role in her investigations. Her character is often portrayed as introspective and emotionally complex, navigating the challenges of her profession and personal life.