One aspect is the use of psychological analysis. In the movie, as in real cases, they try to get into the mind of the killer. For example, Clarice's conversations with Hannibal Lecter are like real - life attempts by investigators to gain insights from a criminal's perspective. Also, the idea of a serial killer with a distinct modus operandi, like 'Buffalo Bill' in the movie, is based on how real - life serial killers often have specific patterns of behavior that investigators look for.