Rather Be the Devil - Ian Rankin

Rebus investigates a cold case that just turned red hot.

As he settles into an uneasy retirement, Rebus has given up his favorite vices. There's just one habit he can't shake: he can't let go of an unsolved case. It's the only pastime he has left, and up until now, it's the only one that wasn't threatening to kill him. But when Rebus starts reexamining the facts behind the long-ago murder of a glamorous woman at a luxurious hotel, the past comes roaring back to life with a vengeance. And as soon as Rebus starts asking questions about the long-forgotten crime, a fresh body materializes. As he connects the mysteries of the past to those of the present, Rebus learns that he's not the only one with an insatiable curiosity about what happened in that hotel room forty years ago, and that someone will stop at nothing to ensure that the crime remains ancient history.