Detective novels usually described shrewd criminals who needed to have extremely high IQ and logical thinking ability to carry out precise murder plans. However, in real life, the intelligence of criminals was not necessarily higher than that of criminals in detective novels. Criminal activities often require a certain economic foundation and resources, and some criminals may lack education and training, lack basic knowledge and skills. In addition, criminal behavior is also affected by many factors such as emotions, motivation, social background, etc. These factors may affect the decision and behavior of the perpetrator. Although detective novels often depicted shrewd criminals with extremely high IQ and logical thinking ability, the IQ of criminals in real life was not necessarily higher than that of the criminals in detective novels.