Showing Silent Partner by Jonathan Kellerman

Dr Sharon Ransom is the most beautiful woman in the room; she's also the most troubled. So when former lover, psychologist Alex Delaware, bumps into her at a lavish LA cocktail party, though still attracted to her, fear of reviving unhappy memories prevents him from offering the help she seems so desperate for. Hours later, Sharon's body is discovered with a self-inflicted gunshot wound. Tortured by guilt, Alex wants answers. As his investigation begins, dark memories of his past with Sharon emerge, and a present full of madness, murder and sexual violence unfolds.