Invisible is a stand-alone novel by prolific American author, James Patterson. It is (co-) written by David Ellis. When Emily Dockery’s twin sister Marta died in a fire, she refused to believe it was an accident. As an FBI research analyst, she began to research similar fires and became convinced that there was a serial killer on the loose. Unfortunately, no one else agreed: not her boss with his wandering hands; not her ex-fiancé, Harrison (Books) Bookman; not the local police; and not her grieving mother.

Despite being suspended from her job, Emmy continues to gather possible cases. Her last hope is that showing him the files on fifty-three such events over the last twelve months will persuade ex-FBI agent Books to come out of retirement and investigate. She’s pleased when this last-ditch attempt gets an investigation started, even is the task force consists of a team of just four.

The narrative is carried mostly by Emmy, with occasional interspersed chapters which are transcripts of dialogue dictated by the murderer: these come across as rather gimmicky. There is some clever investigative work and an exciting climax with a huge twist, but Emmy, despite her brilliance, indulges in a sort of spoiled brat behaviour that is not endearing. Just an OK read that might appeal to fans of serial killer mysteries.