Why are they disappear Jessie Zhao

The book we got to talk about is "4:50 From Paddington" written by Christie, Agatha. The book I was using was published by New American Library. The book's first publishing date is November 4, 1957. This book was talking about homicide is really miraculous homicide, because our sufferer and murder disappear, and our main chapter Miss Marple and her friends find out it have a relation with a really rich family. In this family everyone has their own secret. When we read more we will know what is the thing under everyone. The background of the book is in the 90's. Miss Marple is a really claver old lady, and our murder is not that claver, but he or she is courage.