A message from a dead acquaintance prompts a bus tour to an unknown crime?

In utter disbelief Miss Marple read the letter addressed to her from the recently deceased Mr Rafiel ? an acquaintance she had met briefly on her travels.

Recognising in Miss Marple a natural flair for justice, Mr Rafiel had left instructions for her to investigate a crime after his death. The only problem was, he had failed to tell her who was involved or where and when the crime had been committed. It was most intriguing.