The Killing. Jaz Crealey series, #1

Jaz Crealey is rebuilding her life after the tragic events leading up to the death of her husband. She has a new partner in Sal, a long-term friend who has now become a mainstay in her life. It is in her role as a professional counsellor, Jaz meets Susan, a woman who has led a troubled life, first as a long-term carer for her elderly, domineering mother and then as a victim of an abusive relationship.
Jaz finds herself become so embroiled in this woman's life that she has overlooked problems much closer to home. Issues, which in the modern world of computers and social media quickly become every mother's worst nightmare. Finding out her own daughter has been groomed, then abused by someone she met on-line, Jaz sets out, with Sal's help, to find this abuser while protecting her daughter from further intrusions in her life and merciless bullying from those she had once considered to be her friends.
Then, as Jaz delves deeper into Susan's life, the seedy world of sexual exploitation reveals uncomfortable links which eventually lead to a violent death with its aftermath threatening to turn Jaz's world upside down.