A Question of Ghosts by Cate Culpepper

Becca Healy always believed she understood the shameful circumstances of her mother's death--until the night her mother's spirit whispers a simple message out of the static of a radio: 'Not true.' Becca turns to the terse Dr. Joanne Call, an expert in Electronic Voice Phenomenon--ghost voices--to unravel the mystery of this decades-old tragedy. Joanne can coax messages out of the silence of the grave, but coping with this feisty, emotional Healy person might be completely beyond her. Together, Becca and Jo must tackle childhood grief, a serial killer, Xena withdrawal, and a growing attraction between the two most mismatched women in Seattle.