Graham, Heather. Bone Island trilogy #1

"There are those who walk among us who are no longer alive, but not yet crossed over. They seek retribution, vengeance, to warn. Among the living, few intuit their presence. Katie O'Hara is one who can. As she's drawn deeper and deeper into a gruesome years-old murder, whispered warnings from a spectral friend become more and more insistent. But Katie must uncover the truth: could David Beckett really be guilty of his fianceé's murder? Worse--the body count's rising on the Island of Bones, and the dead seem to be reenacting some macabre tableaux from history."--P. [4] of cover