The crime methods of detective novels can be referred to the following examples: 1. Kidnap: Kidnap the target to a remote place and then extort a ransom. 2. Murder: Using poison or a knife or gun to deliberately injure or kill. Robbery: Use violence or threats to seize property. 4. Fraud: Using false information or means to deceive others to obtain property. 5. Theft: Stealing other people's property through deception or concealment. 6. Love Letter Fraud: Using love letters, text messages, and other channels to cheat others of their feelings or property. 7. Hacker attack: Invasion of other people's computer systems, network accounts, etc. through technical means. Fake and inferior products: The production of fake and inferior products to deceive consumers. 9. Drug dealing: Obtaining economic benefits through drug dealing while harming the health of others. 10. Internet fraud: Using social networking platforms, search engines, and other online platforms to commit fraud. The above are some common criminal methods. Of course, when writing detective novels, you can also add some more unique and thrilling plots and methods to make the readers more surprised and excited.