Distant Echo, Paperback/Val McDermid

In this standalone psychological thriller from the Gold Dagger-winning crime fiction icon, four drunken students find a body in a Pictish graveyard and become suspects in the murder. When the case is reviewed twenty-five years later the four remain suspects, but two of them proceed to die in suspicious circumstances. The two left set about finding what really happened all those years ago, to maintain their freedoms and also their lives.