Birthdays for the Dead

Detective Constable Ash Henderson has a dark secret ...
Five years ago his daughter, Rebecca, went missing on the eve of her thirteenth birthday. A year later the first card arrived: homemade, with a Polaroid picture stuck to the front -- Rebecca, strapped to a chair, gagged and terrified. Every year another card appears, each one worse than the last.
The tabloids call him The Birthday Boy. He's been snatching girls for twelve years, always in the run-up to their thirteenth birthday, sending the families his home-made cards showing their daughters being slowly tortured to death.
But Ash hasn't told anyone about Rebecca's birthday cards -- they all think she's just run away from home -- because if anyone finds out, he'll be taken off the investigation. And he's sacrificed too much not to be there when they finally catch the psycho who killed his little girl ...