Bad Intentions by Karin Fossum

Bad Intentions starts with a death.  Three friends, Jon, Axel and Reilly, have gone on a weekend visit to a lake.  Jon has been hospitalized with depression, and his friends think a change of scenery might be helpful.  They take Jon out on a boat ride, but he takes the opportunity to step over the side and drown himself.  Worried about what the police will think, the two remaining friends hide what has happened and pretend that they woke up to find Jon missing.

As the story unfolds, the reader starts to piece together what lies behind Jon's actions.  Jon leaves enough clues behind that his mother, his doctor and his new girlfriend all inform the police that his depression came from a feeling that he had committed a heinous crime.  Inspector Sejer, assigned to the case, realises that without any forensic evidence of wrongdoing that it is unlikely he will be able to prove the men's collusion in what has happened to Jon.  Then the next body shows up....

Karin Fossum is one of Nordic noir's shining stars.  Bad Intentions is the seventh in her series of Inspector Sejer cases.  The action is more psychological than grisly or action-driven, and the clues mount up as the truth is slowly revealed.  This book is recommended for mystery readers.