What is the difference between real crime solving and speculative fiction?

Detective reasoning novels are novels in which the mystery of the story is solved by deduction (most of them are to find out the murderer). Usually, the story contains a murder case and a detective, but some of them do not have murder as the main plot direction, such as finding a lost object or solving the mystery of a strange event. It is also called detective fiction, but it is not always the detective who solves the mystery. The popular image of speculative fiction in the speculative fiction world is the so-called Bengali school - generally considered orthodox speculative fiction, or mainstream speculative fiction, that is, speculative fiction in which the reader reads and enjoys solving the mystery with the clues provided by the author, or at least speculative fiction in which the main focus is on solving the mystery. Usually easier for the majority of reasoning mystery respected. The traditional detective novel is composed of four parts: 1. a mysterious setting; 2. a tight plot, including the introduction of the detective, a list of facts and clues to the crime, an investigation, an announcement of the detection of the case, an explanation of the detection, and an ending; 3. characters and relationships between the characters, with four types of characters: the victim, the criminal, the detective, the detective's friends, and the good guys who get involved in the crime; and 4. a specific story. Background. The order of these four parts can be arranged and combined as needed, but they are the basis of the structure of the traditional detective novel.