Celine by Peter Heller

This is a mystery frosted in great characters and sprinkled with humor.  Celine Watkins, New England blue blood turned crusty Brooklyn PI, isn't sure being 70 is cause for retirement. When Gabriela Lamont calls her and begins to share her story, Celine and her partner in crime husband Peter think that they may take at least one more case.  Over 20 years ago, Gabriela's father, a famous photographer for National Geographic, was supposedly killed by a bear just outside of Yellowstone.  This made Gabriela a wealthy woman but she never believed her father was actually dead.  She begins a search on her own but eventually hits a wall and contacts Celine. Skeptical at first,  when Gabriela's research file disappears, Celine's instinct kicks in and the search begins.  There  is a lot of interesting back story to both women's lives and Peter is a delight. Gotta love 70 and still up for adventure.