The Burning Girl by Mark Billingham

When a series of gangland killings leaves victims marked with an X carved into their backs, DI Tom Thorne suspects a ruthless contract killer is at work. Meanwhile, a case from twenty years earlier resurfaces when the retired detective who investigated it asks Thorne for help.

As Thorne investigates both cases, he uncovers links between past and present that lead into London's criminal underworld, where old secrets and violent rivalries refuse to stay buried.

The Burning Girl is the fourth novel in Mark Billingham's Tom Thorne crime thriller series, combining police investigation, gangland conflict and psychological suspense.