Walking into the conference room with Xia Shi, Gu Song immediately felt that the eyes of his colleagues were full of expectations or doubts and curiosity. Originally, he only temporarily joined the task force to help Xia Shi, but at this moment, he felt a heavy weight on his shoulders.

Director Xia sat at the end of the rectangular conference table, nodded slightly at Gu Song, then snuffed out the cigarette butt in his hand and said to the participants: "Everyone is familiar with this colleague, so I won't introduce it." I hope that in the next process of handling the case, you can still cooperate as tacitly as before. Okay, without further ado, let's get started. Director Chen, let's talk about the situation you have over there. ”

"Okay." Forensic Doctor Chen nodded, projected the slides on the big screen in the conference room, and introduced in an orderly manner while playing the scene and autopsy photos, "The victim in this case is named Xu Zilin, male, 47 years old this year, who lives in Room 202, Building 46, Tianhe Community, Xishan Street, Xuanyang District, and ran a small stall selling egg scones near Xishan Middle School, which is about 1.4 kilometers away from his home.

"The autopsy results showed that the victim died on September 29, between 10:30 and 11:30 last night. The victim suffered from a single-edged sharp object that caused a ruptured heart and penetrated the lungs, resulting in acute hemorrhagic shock and dyspnea. In addition to the two fatal wounds on the chest, there were 40 wounds on the victim's body caused by the same sharp object, most of which were non-reactive and were inflicted after the victim's death.

"After identification, the murder weapon used by the murderer was a single-edged knife with a width of 3 centimeters and a blade length of 13 centimeters, which is highly similar to the murder weapon of the '9/16 case'. In addition, the victim's lips were pierced by four steel nails with a length of 50 mm and a diameter of 2.8 mm, which also perfectly matched the characteristics of the 9/16 case.

"The only difference is that in this case, the victim had a blunt force blow to the back of the head, presumed to have been inflicted when the killer attacked the victim. The bloodstained murder weapon has been found in the alley where the victim's body was found, and is a mutilated paving stone, which should have been picked up by the murderer on the side of the road, and no valuable fingerprints have been found on it. From the perspective of forensic science, I believe that it is highly likely that the '9/16 case' and the '9/29 case' were committed by the same murderer, and I recommend that the two cases be investigated together. ”

"In fact, we are already investigating the social links between the two victims." As soon as Forensic Doctor Chen's words fell, Xia Shi took over and said, "Because the details of the '9.16 case' are only known to the murderer himself, except for us who handle the case, the possibility of imitating the crime is almost non-existent." At present, we can basically determine that He Yao, the victim of the first case, and Xu Zilin, the victim of the second case, do not know each other, and there is no intersection in their lives.

"The murderer must have a reason for choosing these two victims with such a huge difference in gender, age, and life background, and this is also an issue that we urgently need to figure out at present.

"Regarding the suspects, we have locked up two people before this, namely He Yao's boyfriend Ma Zhichen, and Deng Jun, a water and electricity repairman who made an appointment to come to He Yao to repair the toilet tank on the day of the crime. According to Gu Song's proposal, colleagues from the technical team revisited the scene of the '9.16 case' this afternoon and found a trace amount of human dander tissue under the lid of the toilet tank. DNA extraction and alignment are being carried out in a hurry, but ......"

Speaking of this, Xia Shi couldn't help but let out a slight sigh, "Judging from the two cases, I don't have much hope for the results of the DNA comparison. One of the reasons is that our number one suspect, Ma Zhichen, has been staying in the interrogation room of the criminal police team since 9 p.m. yesterday. Now that we have determined that the two cases were committed by the same murderer, Ma Zhichen is definitely not the murderer we are looking for.

"The second reason is that Deng Jun did not have a criminal motive to kill He Yao, if he had to say it, it could only be that the two parties had a quarrel over something in the process of contact, which eventually led to a crime of passion. Crimes of passion often have the characteristics of suddenness and accidentality, and rarely form continuous crimes, so I don't think Deng Jun is the murderer of these two cases. In other words, we may have to look for the suspect again. ”

"Don't jump to conclusions." Director Xia didn't quite agree with Xia Shi's point of view, "There are still some doubts about Ma Zhichen and Deng Jun, you should hurry up and thoroughly understand the problems of these two people." In addition to this, continue to investigate around Xu Zilin's social connections to see if there are any suspicious people around him. After Director Xia finished speaking, he looked at Gu Song with a gaze full of expectations, "Xiao Gu, you are also a member of the task force now, just say what you think." ”

The conference room suddenly fell silent, and everyone was looking forward to Gu Song's speech. This feeling of being over-concerned made Gu Song, who had not participated in solving the case for half a year, a little uncomfortable. He turned his head to look at Xia Shi who was sitting next to him, the latter smiled and nodded at him, only then did he regain his former self-confidence, and said bluntly to Director Xia: "Xia Bureau, with all due respect, your current thinking on handling cases may be somewhat limited. ”

"Oh? So what good advice do you have? Director Xia raised his eyebrows, and instead of being angry, he made a deaf look.

"As things stand, the motive of the murderer is still an issue that deserves further investigation, and the modus operandi is very different from previous cases. If the purpose and significance of the murderer are not clear, it will be difficult for us to lock down the suspect through conventional investigations. Of course, the suspicions of Ma Zhichen and Deng Jun still need to be investigated in depth, and the social relationship between the two victims needs to be further sorted out......"

Gu Song paused, looked around at the colleagues present with a serious expression, and said slowly: "I know that some people may not know much about criminal psychology portraits, or they don't believe in that seemingly mysterious way of solving cases at all. However, considering the particularity of the case, I still suggest that on the basis of the original idea of handling the case, use portrait technology to narrow the scope of investigation, and strive to arrest the murderer before he commits the next crime. ”

"Speaking of criminal psychology portraits...... Xia Shi suddenly remembered a name that was often on someone's lips, turned to Gu Song and said, "There is someone who is quite suitable for this job." ”

R University of Municipal Law.

In the last class before the National Day holiday, many students' minds were no longer in class. Although the tall, good-looking female teacher on the podium was telling the content in a pleasant voice that was not too boring, it still couldn't stop the students from deserting underneath.

"Anyone who enters the crime scene takes some of the items from the scene and leaves some of the items that were brought in. This is the 'Locar Communication Principle' proposed by the French criminologist Edmond Locar at the beginning of the 20th century. Lokar was referring to physical evidence, such as fingerprints, hair, fibers, bloodstains, dirt, etc., but it was not only physical evidence that the killer left at the scene, his statement also applied to traces of psychology. ”

The female teacher flipped through the electronic courseware and glanced at the students with her peripheral vision, and her two slender eyebrows gradually wrinkled. "Every offender leaves at least one or more traces of behavior, such as modus operandi, characteristics, personal characteristics. Every crime has a modus operandi, but not every murderer has characteristics. Distinguishing between techniques and characteristics is the basic job of every psychographer......"

At this point, the female teacher's voice stopped. She lowered her gaze to the penultimate row of the lecture hall with a vague smile on her face.

"An Ziyang." She called out a fat boy who didn't know what to talk to his classmates in the back row and smiled, and asked pretending to be serious: "Explain what is the technique?" What is a feature? ”

"Uh, this ......" An Ziyang scratched the back of his head in embarrassment, laughed innocently twice, and then turned his head, looked at the male classmate next to him who seemed to be listening to the lecture with a pleading eye, and asked in a low voice, "Jin Yu, what was she talking about just now?" ”

"Methods of Crime and Characteristics of Crime." The male classmate whispered with his hand to his mouth, and did not forget to sarcastically say to the other party after speaking, "You are a pig's head." ”

"Xia Jinyu." The female teacher glanced at An Ziyang's side, and the corners of her mouth rose slightly, "You are so helpful, then help him answer this question." ”

Xia Jinyu stood up slowly, and almost at the same time, many female classmates in the classroom looked back at him, and some even showed a nymphomaniac smile.

Xia Jinyu had long been accustomed to it, and calmly looked at the podium in front of him and replied: "The method is the behavior that criminals must carry out in order to commit a crime; And the characteristics of the crime are the manifestations of the murderer's heart and fantasies in the criminal act, what the murderer does for himself, whether it is necessary or not. ”

"Can you give an example of how the same act can mean different things in different murderers?"

Xia Jinyu thought for a while and continued to answer: "Suppose that in a certain case, in order to hide the crime, the murderer has to divide the victim's body into several pieces for easy disposal and disposal, then dividing the body is his method; However, for some psychologically abnormal murderers, the dismemberment of the body is not a necessary method to conceal the crime, but they can feel the stimulation and enjoyment from such behavior, and the dismemberment is the characteristic......"

"Teacher." As soon as Xia Jinyu finished answering, a girl sitting in the front row took over the conversation, "Five years ago, there was a corpse killer named Yu Chiliang in R City. His family is very rich, very handsome, and has a high IQ, but because of his special upbringing, he has been psychologically twisted since he was a child, and finally brutally murdered six girls who lived with him in his twenties, and buried their bodies in pieces in the courtyard of his villa. I think his case is very valuable for research, when will you tell us more about his case? ”

"Oh, I've heard of that case......"

"yes, how come I don't know......"

"I think I've seen it in the news, but I was still in junior high school at the time, so I didn't pay much attention to ......," the classmates in the room began to chatter, obviously very interested in the case mentioned by the girl. They prefer to listen to some heavy-tasting examples rather than boring theoretical knowledge.

"Okay, I'll collect some information when I have time." The female teacher promised on her lips, but she didn't know much about the case that year. When she looked at Xia Jinyu again, she found that the other party was still in the posture of answering the question just now, and the expression on her face was elusive.