The Son by Jo Nesbo

Sonny Lofthus has spent more than half of his life in prison.  He was a popular student, a wrestler winning awards, when he came home to find the father he idolized dead by his own hand, a suicide note confessing to being a corrupt policeman.  Sonny and his mother go into tailspins as their grief overwhelms them and after his mother's death, Sonny becomes a heroin addict.  Desperate to ensure a steady supply of drugs and caring little about his life, he confesses to two murders for Oslo's top crime lord, The Twin, and is sentenced to life in prison.  He is relatively happy there as he is guaranteed a steady supply of drugs.  He becomes an icon, the man who listens to everyone's sins and forgives them, no matter how heinous.

Sonny's life changes after eighteen years when a long-time inmate comes to him for confession before his death.  He confesses that Sonny's dad was not corrupt, that instead he was investigating the corruption in the police force and that he was forced to write the suicide note before he was murdered.  This wakes Sonny from his years long stupor and he determines to find out who killed his father and make them pay. 

Escaping from prison, Sonny soon makes a major stir in Oslo.  He starts at the bottom of the Twin's organization, working his way up and extracting confessions.  But now instead of forgiving he kills the men involved in taking everything from him.  This is no clandestine operation.  Both the police and the criminals know who is responsible for this wave of destruction.  Inspector Simon Kefas is put in charge of finding Sonny.  He was Sonny's dad's best friend and wants to find Sonny before The Twin finds and kills him.  Who will emerge victorious in their quest; Sonny, The Twin or Kefas?

Jo Nesbo is known for his Harry Hole series.  This is a stand alone novel although Sonny has similarities to Harry.  Both are flawed men, driven by addictions they entered to deal with the horrible blows life has dealt them.  Both have an inner goodness that allows them to do anything in order to set their worlds right and both pay the price in remorse and a sickness at what their mission extracts from them.  This book is recommended for mystery readers.