They Do It with Mirrors by Agatha Christie is a Miss Marple mystery where she helps out her old friend by investigating the murderous happenings at her home and corrective center for first delinquents.
Agathon The Big Four Is it me or was this a really, really weird story? It’s like all of the early Agatha spy and espionage capers got crammed into a Poirot tale, and he’s spending most of his time pretending valiantly that he’s not in the wrong book.
“Women observe subconsciously a thousand little details, without knowing that they are doing so. Their subconscious mind adds these little things together—and they call the result intuition.” ― Agatha Christie, The Murder of Roger Ackroyd