When Birds Fall Silent by Shana Frost

A cold case threatens to shatter Callan’s career. Blaine Macgregor vanished on a summer’s night fifteen years ago. Now, DI Callan Cameron is investigating his case one last time. But for Callan it means unearthing a bygone summer he’d rather forget.
 Amateur sleuth Aileen Mackinnon overhears a guest’s puzzling conversation and can’t stop asking questions. Is she being duped again? With Callan refusing to open up about his case, Aileen needs a distraction. What better than a case of her own? As Aileen and Callan balance on a thin rope of betrayal and trust, one question haunts them: Is Blaine still alive?