All the Blue-Eyed Angels - Erin Solomon Mysteries , #1

Jonestown. The Solar Temple. Heaven's Gate. In the summer of 1990, the Payson Church of Tomorrow joins the ranks of those infamous cult suicides when thirty-four members burn to death on a small island off the coast of Maine. At ten years old, Payson member Erin Solomon watches helplessly as the church and its congregation are reduced to ash and embers. More than twenty years later, Erin is an accomplished investigative journalist when she receives word that she has inherited Payson Isle...
and all its ghosts. She returns to Maine to learn the truth behind the tragedy that has haunted her since childhood, aided by the rakish mentor who's stood by her side since she was a teenager, her trusty mutt Einstein, and a mysterious stranger with his own dark past. Soon, Erin is enmeshed in violence, conspiracy, and scandal, as she fights to unearth the secrets of the Payson Church of Tomorrow -- secrets someone will kill to keep buried.