Criminal Investigation Notes
Criminal Investigation Notes: Chapter 16
Su Hui stood up, and he leisurely introduced: “This is just a simple schematic diagram, time is limited, I didn’t draw it in a standard way, it’s merely a pretext meant to introduce the theory to everyone. The method I used today is actually not one that everyone understands. It is a branch of the criminal psychological profile, which is called Geographic Profiling, that is, the criminal geography profile. Its principle is to link the perpetrator and the victim with data such as the encounter location, attack location, murder location, and body disposal location to create the criminal psychological profile, and deduce the criminal’s residence, the location of the dismemberment, the place of work, or the possible stopover.”

Su Hui continued to say: “Actually, this theory just sounds advanced, and there were some sayings among many old detectives in the past, for example ‘abandon it far, bury it close’, ‘head far, body close’, ‘a little near but far away’,  ‘not close, not far, not repeating’. In fact, these are the basic principles of criminal geographic profiling, but what I deduce now is more systematic.”

Then Su Hui turned around to face the crowd and explained in detail: “If there is no crime location, there will be no crime. The choice of location by criminals is not *random, we need to look for the rules, and there are some basic theories, which everyone may also understand. For example, the Circle Hypothesis Theory, that is, the circle of crime: the distance of a straight line connecting the two most geographically distant cases in a series of homicide cases is the diameter, and the focus of the line is the center of the circle, forming a circle at a time.”

Show/Hide Note(杂乱无章) disordered and in a mess (idiom) – Fig: All mixed up and chaotic

Su Hui’s voice was a little low, and he talked eloquently, looking like a teacher who was teaching students, but now, all the criminal policemen who had worked in the Major Crimes Unit for several years were in front of him.

“…and the Environmental Criminology Theory and the Principle of Foraging are some of the theories that underlie criminal geographic profiling. Crime only happens when the perpetrator and the potential victim are in the same place at the same time, and now we’re in in the era of big data, geographic information used by police should be combined with crime maps and applied in practice.”

In the conference room, everyone was silently and attentively listening to Su Hui’s explanation for a while.

Although some of them had heard of these theories, they did not have such a deep understanding, and they had no experience in applying them to practice.

“Although the actual clues we have now won’t allow us to find the murderer right away, they have already given us a lot of information…”

As he spoke, Su Hui tapped the three red dots on the picture with a pen, “These three places are the places where the murderer stored the stumps and handed them over to the client. According to the testimony, we can know that these places were selected by the murderer.”

Then he clicked the three yellow dots next to them: “These three places are the original work places of the waitresses before they disappeared. We have already learned about these places, which means that the murderer has been to these places at some point in time. .”

Su Hui, using these points as the center, used his mouse to draw several intersecting circles.

“Several geographic profile models commonly used in the world are the Rossmo model, Canter model, and Caining model. I used the police’s GIS here. Based on these locations’ information, we can furthermore optimize it according to the city topography, and we can deduce the next map, that is  to help us find the source of the crime…”

Having said that, Su Hui closed the previous schematic diagram and opened a professional software.

A rainbow-colored map of Huadu appeared on the projection.

Su Hui circled the red part of the picture with the mouse and concluded: “It can be known from the calculation that the suspect’s fixed attribution point is likely to be within this area.”

Su Hui’s explanation was not complicated, and he omitted many parts that need to be calculated. It sounded easy to understand and had a sufficient theoretical basis.

Qu Ming heard this, looked at the map on the screen, and coughed lightly.

Xia Mingxi had only heard of some relevant theories before but had not put them into practice. She felt that Su Hui explained it very well, but she still had to nitpick: “Yes, but this area is still very large…”

“Yes.” Su Hui nodded in agreement.

Xia Mingxi didn’t expect Teacher Su would address her so straightforwardly, she pursed her lips, wanting to hear what he would say next.

“Eve with the current Major Crimes Unit and the police force of the General Bureau, such a large area would need to be investigated for a long time. Therefore, based on the murderer’s means of transportation, class, age, education, and the necessary conditions for committing the crime, the geographical location is again adjusted through rigorous screening.”

Qu Ming asked: “What are your screening conditions and criteria?”

“It’s the unique behavior pattern of the murderer.” Su Hui said, leaning his body on the table, and holding the cat’s head on the scepter with the other hand, “For example, why is his victim a coffee shop clerk? ?”

Xia Mingxi thought for a while: “The murderer is a person who likes elegance and is fond of drinking coffee?!”

Su Hui said: “It is quite probable that he likes elegance, however, his fondness for coffee is incorrect. The murderer’s multiple purchase receipts did not show coffee, nor did he drink coffee in the coffee shop. This is also one of the distinctive characteristics of the murderer. I think that the coffee shop itself has a certain significance to the murderer. Also, our screening conditions are related to his age, education, and financial status. This is not discrimination, rather it is science. Most of the bottom lowest rung workers are unlikely to frequently come and go to coffee shops and furthermore stay there for long periods. Their time, as well as economic situation, do not allow it.”

Zheng Bai followed his train of thought and thought deeply: “In other words, the murderer chose the coffee shop for a reason…”

With Su Hui’s mouse click, the colors of some areas near farmers’ markets, construction sites, and other areas were dimmed, and the number of areas to be investigated was reduced by a lot.

“According to several surveillance reports, the time of the murderer’s visit to the coffee shop is not fixed. Most of the time is in the afternoon. What kind of work might he be doing?” Su Hui continued.

“It should be a job with relatively free time…or a job with changing shifts…” Qiao Ze answered.

Su Hui coughed twice and continued: “Those low-level employees who live in groups, or busy white-collar workers, have relatively little personal space and time, and it is difficult to make others unaware. According to these conditions, we can carry out filtering to exclude a few more areas.”

The area on the map is further reduced.

“Then the next question, his means of transportation should be a private car, how did he choose those coffee shops? Where did he change into the women’s clothes? When did he commit the abduction? Where did he then take the victim? Furthermore, after the hands and feet were cut off, what did he do with the rest of the body? Where was it stored?”

Everyone couldn’t help but follow Su Hui’s voice and ponder these questions.

“I read the time of the women’s disappearance, and also read the forensic report. The murderer did not cut off their hands on the day of the murder. He may have kept them for a period of time, and he must have had to go back and forth many times. The place where the body is imprisoned and dismembered must be large enough, quiet enough, and safe enough not to be noticed.”

Su Hui continued: “At the time of inference, the murderer’s dismemberment operation room is fixed, and once the coffee shop is selected, it is fixed, which gives us more hypothetical routes. And when the murderer performs dangerous activities, he will take the initiative to avoid the downtown area.”

Having said that, Su Hui’s mouse clicked on another point, and several simulated paths represented by dotted lines appeared on the map.

Then, several small circles of different colors appeared on the map.

Su Hui raised his head and concluded: “At present, I can ascertain that the murderer’s dismemberment location may be located in these red areas, and his residence is likely to be in the blue area. If his residence is also the place where the corpse is dismembered, then it will be in the purple area, and the darker the color, the greater the possibility.”

If the first picture Su Hui showed was rough and rudimentary, the later pictures became more and more professional, and now this picture could be described as high-end.

This Teacher Su really used ten minutes to circle the possible hiding places of criminals with a method that they could understand…

The whole process was like magic.

Lu Junchi stood with his arms folded, watching as Su Hui’s explanation deepened, the expressions on the members’ faces changed from initial doubts to admiration and surprise. He said to the several subordinates: “You can start with the dismemberment site, focus on the purple area, and also inspect the blue and red areas.”

The crowd kept nodding.

Su Hui recalled something and reminded: “By the way, what I did is just a data model, which can only be used as a reference for the judgment, and it is based on the fact that there is only one murderer and so on. You still have to be cautious and serious, use actual evidence for the operation and some special cases cannot be ruled out…”

Lu Junchi nodded slowly: “We will integrate the real situation.”

Su Hui held the scepter, hesitated for a moment, and then said: “Because the time is a little tight now, I will make another bold prediction…”

Seeing that he hesitated, Lu Junchi nodded and said, “Teacher Su, don’t worry, we will only use it as a reference.”

After several contacts, he knew that Teacher Su was very taboo against unsubstantiated psychological profiles, and he was afraid that they would take this as a criterion and ignore other clues.

Su Hui then continued: “There are 232 cafes in the entire range of the murderer’s activities. Some of these cafes are too big or too small, and some are too biased. These are not in line with the murderer’s selection pattern. After screening, a total of 34 basically match, and he has committed crimes in three of them, which means that the murderer will give up and continue to commit crimes in some coffee shops near these three. ”

The cafes on the map were darkened one by one, and finally, there were only five light spots left, which were still flashing.

Su Hui pointed to the results in the picture below and said, “The murderer’s next murder location is likely to be within a week, in these five cafes.”

Anyone else thinks this Geographical Profiling is insane? I checked on some of the concepts and let me say, it made me want to drop everything and start studying criminology. Coz how do you find out a person’s entire life using basic things like locations one has visited? It’s scary and intriguing. This is taking doxxing to a whole other level. 


Certified member of the IIO(International Introverts Organization), PhD holder in Overthinking and Ghosting, Spokesperson for BOBAH(Benefits of Being a Homebody), Founder of SFA(Salted Fish Association), Brand Ambassador for Couch Potato fall line Pajama set.

  1. Rosula D. has spoken 9 months ago

    Tbh, this concept of Geographical Profiling shows how predictable we are as humans. Have enough data, which doesn’t necessarily mean a big volume, and you can probably predict most people’s behavior. This is why governments and companies are willing to do pretty much anything to get data; they understand how valuable they are. And with the more sophisticated algorithms we’re getting, in a few years our actions will be 100% predictable and easier to influence. (Not saying this in an insidious way, just think how product recommendations or TikTok works.)

  2. Rottenkani has spoken 9 months ago

    ok time to read the next chapter

  3. qyura has spoken 10 months ago

    This is amazing. Su Hui is amazing & intelligent. I wonder how it feels to be this smart.
    Thank you so much for your hard work!


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