Who killed Alex?

International best-seller in 10 countries.  Over 41 million reads.  Wattys Award.     Hannah  is a sixteen-year-old student hooked on social media. One day, she receives a friend request on Facebook from a boy named Alex Crowell. After accepting it, Hannah discovers that Alex is missing and that he is given up for dead. However, an eerie event takes place: Hannah gets a message from the boy, who asks for help to find out who killed him. From that moment, she will start an investigation to track down the killer with Alex & apos;s ghost help. But facing the truth won & apos;t be easy for either of them…