Why Didn't They Ask Evans?

When Bobby Jones found a dying man at the foot of a cliff beside a golf course, he stood in the shadow of his own death. But Bobby was lucky — lucky to escape being poisoned, and lucky to have the quick-witted Frankie, otherwise known as Lady Frances Derwent, to help find the would-be murderer. Their only clues: a photograph and the dead man's last words: Why didn't they ask Evans?