The Spellman files - Lisa Lutz

Izzy Spellman is 28, single and works for Spellman Investigations, a family-run private detective agency. She might have a chequered past littered with romantic mistakes - but at least she's good at her job. Invading people's privacy comes naturally. To the whole family. To be a Spellman is to snoop on a Spellman; tail a Spellman; dig up dirt on, blackmail and wiretap a Spellman. But when Izzy's parents hire her 14-year-old sister to discover the identity of her new boyfriend, Izzy decides she wants out. Before they'll let her go, her parents ask her to solve one last case - a 15-year-old, ice-cold, missing person, impossible-to-solve case. But when a disappearance occurs far closer to home, Izzy's Impossible Case becomes the most important of her life.