Why do we seek explanations for most mysterious events but prefer some when they're unresolved? That's the discussion with Anne McElvoy today, including Val McDermid who uncovers the secrets of forensic science, Susan Hill exploring suspense and atmosphere in ghost stories, Alex Werner from the Museum of London's new Sherlock Holmes exhibition and Dr David Clarke, who reveals the official accounts behind well known paranormal events.

Producer: Simon Tillotson.