Tian Tian took out an old textbook and said, "This is my textbook on criminal psychology in college. I've been looking through it all this time, trying to sharpen my gun. According to classical theory, serial killers generally choose their victims according to their availability, vulnerability and agreement. If Jiang Changsheng, Wang Tao, Zhu Jianwei and Chen Lei are all killers, then the usability and vulnerability are obviously inconsistent. "

Hou Dali graduated from Shannan Criminal Investigation Department, studied criminal psychology, and understood what Tian Tian meant.

To put it bluntly, available means two situations: in the first case, the victim's lifestyle makes him have the opportunity to be trafficked; In the second case, no one cares after being trafficked or killed. Jiang Changsheng, Wang Tao, Zhu Jianwei and Chen Lei do not belong to these two situations, so the murderer did not consider "availability" when considering the problem.

Vulnerability refers to the degree to which victims are vulnerable to attack. These four men are all adult men, and Jiang Changsheng is a vegetable farmer with a strong body. Chen Lei is a social person with a knife and a gun; Zhu Jianwei is tall and likes outdoor activities. Only Wang Tao is slightly weak and the only one who was stabbed with a knife. From this perspective, the murderer did not consider whether the opponent was vulnerable when considering the problem.

Desirability means that the victim conforms to the preference of the murderer, which may involve the characteristics of the victim, or other motives, or other characteristics.