Past Lying by Val McDermid

Edinburgh, haunted by the ghosts of its many writers, is also the cold case beat of DCI Karen Pirie. So she shouldn’t be surprised when an author’s manuscript appears to be a blueprint for an actual crime. Karen can’t ignore the plot’s chilling similarities to the unsolved case of an Edinburgh University student who vanished from her own doorstep. The manuscript seems to be the key to unlocking what happened to Lara Hardie, but there’s a problem: the author died before he finished it. As Karen digs deeper, she uncovers a spiralling game of betrayal and revenge, where lies are indistinguishable from the truth and with more than one unexpected twist.