The Valley of the Shadow (Thorndike Press Large Print Mystery Series)

While out on a walk, Eleanor Trewynn, her niece, and her neighbor spot a young, half- drowned Indian man floating in the water. Delirious and concussed, he utters a cryptic message about his family being trapped in a cave and his mother dying. The young man is whisked away to a hospital, and a desperate effort is mounted to find the missing family-- who the local police inspector presumes are refugees from East Africa abandoned by a smuggler.