A killing of angels

The first death looked like a suicide. But someone had tucked a picture of an angel and a handful of white feathers into the banker's pocket - before pushing him in front of a Tube. A killer is stalking the Square Mile, an avenging angel intent on punishment. But why these victims? What were their sins? Psychologist Alice Quentin swore she'd never get involved with police work again. Her duty is to the living, not the dead. But she owes detective Don Burns a favour, and when he comes begging for help, how can she refuse?