The Ghost in the Ice House. Crystal Cove Cozy Ghost Mysteries, #2

Sally O'Brian sees ghosts. Not   because she wants to. But when someone tried to kill her and her husband, she discovered that while his time had come, hers had not. Now she was back in this plane of existence, but this time with a mission. Her role in life was to help those who could not pass over to the other side to do so. And that mission included the plaintive voice of a young teenager who had witnessed the murder of a young man in the Cliff House.  And the ghost was willing to help Sally solve the current-day murder, but only after Sally had found out who had killed the unfortunate teenager eighty years earlier.