Book excerpt: The basis for the hit series "Shetland" now airing on PBS. Winner of Britain's coveted Duncan Lawrie Dagger Award, Ann Cleeves's Raven Black introduces a dazzling suspense series to U.S. mystery readers. It is a cold January morning and Shetland lies beneath a deep layer of snow. Trudging home, Fran Hunter's eye is drawn to a splash of color on the frozen ground, ravens circling above. It is the strangled body of her teenage neighbor, Catherine Ross. The locals on the quiet island stubbornly focus their gaze on one man--loner and simpleton Magnus Tait. But when detective Jimmy Perez and his colleagues from the mainland insist on opening out the investigation, a veil of suspicion and fear is thrown over the entire community. For the first time in years, Catherine's neighbors nervously lock their doors, while a killer lives on in their midst.