Thin Air by Ann Cleeves

Thin air is the sixth book in the Shetland series by Ann Cleeves, the number one bestselling author and creator of Vera, Shetland and the two rivers series. The sixth Shetland novel a killer who leaves no trace… A group of old University friends leave the bright lights of London and travel to Shetland to celebrate the marriage of one of their friends to a local. But late on the night of the wedding party, one of them, Eleanor, disappears – apparently into thin air. Detectives Jimmy perez and Willow Reeves are dispatched