[1] She is the daughter of the protagonist, Peter Decker, a Los Angeles police lieutenant, by his first marriage.
While Cindy and her mother Jan are portrayed as Jewish, they are not as religiously observant as Peter's second wife Rina Lazarus.
Cindy is a teenager in the earliest books, but takes on a more active role in solving crimes in later novels and eventually follows her father into the police force.
In Grievous Sin, Cindy helps care for her infant half-sister Hannah Decker, after her stepmother has a difficult childbirth, and helps investigate the disappearance of another infant from the hospital ward where Hannah is being cared for.
In Street Dreams, Cindy investigates the case of an abandoned infant, and dates and eventually marries a male nurse and Ethiopian-Israeli Jew, Yaakov ("Koby") Kutiel.