City of masks - Daniel Hecht

Seattle-based Lucretia (Cree) Black is a parapsychologist: a professional ghost-hunter. Her company, Psi Research Associates, takes a scientific approach to investigating hauntings, applying in-depth historical research, psychological analysis and empathic techniques.
Hired by Ronald Beauforte, a most reluctant client, to investigate the alleged haunting of his ancestral New Orleans home and save the sanity of his tormented sister Lila, Cree finds herself having to face up to her own haunted past. As she gets closer to the truth and the proverbial bones in the closet of the prestigious Beauforte family come crashing down around her, Cree must struggle to keep her own ghosts at bay.