Heartbreak Hotel by Jonathon Kellerman

Psychologist and police consultant Alex Delaware gets a request for visit from a 100-year-old woman at the Aventura Hotel, a place with a tumultuous past that is now primarily where plastic surgery patients go to recuperate in anonymity. Alex is charmed by the elderly woman, who gives him a large retainer and promises to tell him her story on their next meeting. But the next meeting never happens because she passes away. An astute paramedic thinks the death might not be due to natural causes, so Alex and his police lieutenant buddy Milo are called in. They both wonder what secrets the woman had been about to spill--and whether that might have led to her death. And as they unravel her story, it turns out that she had indeed lived quite the colorful life.

It's kind of a convoluted plot but a good addition to the Alex Delaware collection.