The stranger diaries / Elly Griffiths.

Clare Cassidy is no stranger to tales of murder. As a literature teacher specialising in the Gothic writer R.M. Holland, she teaches a short course on them every year. Then Clare's life and work collide tragically when one of her colleagues is found dead, a line from an R.M. Holland story by her body. The investigating police detective is convinced the writer's works somehow hold the key to the case. Not knowing who to trust, and afraid that the killer is someone she knows, Clare confides her darkest suspicions and fears about the case to her journal. Then one day she notices some other writing in the diary. Writing that isn't hers.