The Last Voice You Hear by Mick Herron

Caroline Daniels meets a terrible end beneath the wheels of a train. Strangely, her new lover Alan Talmadge fails to turn up at the funeral, and private investigator Zoe Boehm is hired to find him. Already struggling to come to terms with her own violent past and its damaging effect on her future, life gets even more complex for Zoe, as she attempts to unlock the secrets of a woman she's never met, in search of a man who might be anyone . . . But as her search leads her nearer to the hearts of two very different kinds of criminal, she starts to wonder whether the man she is looking for has found her first. And, if he has, if that is going to make her another victim - or prove to be her salvation.