The Aosawa Murders

17 poisoned guests. A cryptic note. One survivor. Who could the murderer be?

This was such a fascinatingly written story - although I went in thinking I knew exactly “whodunnit” and “howdunnit”, the mystery of “why” kept me enthralled to the very last page. The book is written as a series of interviews, held decades after the murder, as the unnamed interviewer tries to piece together what happened the night of the murder and the subsequent fallout. 
This is not a book for anyone who prefers their mysteries neatly wrapped up by the end, but if you enjoy books that stick with you for days afterwards, I suggest giving this one a try.