Ada's Death — Gillian Larkin

Cara Daniels has a secret job. She saves the lives of people who are going to be murdered. She also saves the souls of the people who are due to commit the murder.
In book 5, Cara deals with her most difficult case. Her gran's neighbour, Ada Clement is going to be murdered in the next few days.
Cara has known the sweet old lady all her life and can't believe that anyone would want to kill her.
Cara is soon in for a shock.