A Meditation On Murder by Robert Thorogood, 356 pages
When spiritual guru Aslan Kennedy is murdered in a locked room with paper walls, the Saint Marie police are given the impossible task of investigating. Because as he bakes under the hot Caribbean sun, DCI Richard Poole is sure of only one thing: the one person who has confessed to Aslan's murder is the only person that could not have possibly done it.
This novel does not contain any spoilers for any season of the show.