"Geographic profiling? Criminal geography and environmental criminology? If you say this, I won't be sleepy." Liu Jinghui suddenly became excited: "I am also more interested in the crime analysis of the Chicago School. By the way, you said it should be used
If you apply theory to related practice, I have actually done similar cases."
Jiang Yuan talked while walking: "Oh, have you ever done a similar case?"
"Of course. In the past, without you, for some cases without clues, I could only draw circles and visit them. At that time, I made judgments based on the crime model theory..."
"Is it useful?" Jiang Yuan didn't really want to discuss this purely theoretical topic, but he was indeed a little curious.
"Useful. For example, the crime pattern theory believes that the spatiotemporal interaction of crime elements makes the crime most likely to occur in areas where the activity spaces of potential offenders and potential victims overlap. I used this method to catch a serial rapist.
In this method, all the activity areas of the victims are marked, and then the suspect is checked to see if there is an activity area that intersects with these victims..."
Jiang Yuan interrupted Liu Jinghui's eloquence: "Is it easy to do?"
Liu Jinghui was stunned for a moment, and then entered the state of reminiscence. After a while, he said: "After determining the scope, we conducted an investigation and visited, and finally caught the prisoner... It must be difficult to do. I used to do investigation, but I didn't do it like you."
Strength of support.”
Criminal geography and environmental criminology, etc., are all theoretical studies of crime based on geographical factors. Further developments include crime pattern theory, daily activity theory, rational choice theory, crime space theory, etc.
These theoretical things are actually of little use when faced with some small cases. Because small cases can be left unsolved. If you really can't find any clues, just give up.
Most police officers will only use these theories that are out of intuition when they encounter a big case that must be solved.
And foreign aid like Liu Jinghui, even if he fights in the name of a superior unit and uses these criminal theories to solve cases, he will still be regarded as a scholar. The cooperation between various units must be somewhat slack. If the task is too heavy, he will be told in person.
There are also people who make weird things, and things like things that go wrong are commonplace.
Jiang Yuan nodded as if he didn't understand.
Liu Jinghui looked at his dragon's confused look and couldn't help but sigh: "You can't imagine what you haven't seen before!"
"Geography has indeed great restrictions on people. People are prisoners of geography." Jiang Yuan nodded in agreement. Northerners who have never seen the sea can hardly imagine the rough waves on a typhoon day, and southerners who have never seen snow can hardly imagine it.
Imagine the coldness of splashing water into ice.
Liu Jinghui shook his head and said, "I'm talking about handling cases. When we are working on cases outside, sometimes we encounter things that you can't even imagine... It's like you, who have a ranch at home, can't imagine it.
Some people will do strange things just to eat a smoked chicken."
Jiang Yuan glanced at Liu Jinghui sympathetically and curiously.
"I'm fine." Liu Jinghui couldn't bear this, waved his hands and said: "It's all in the past. The grievances I suffered while handling the case are nothing. As long as the case is solved, all the hard work will be recovered in multiples..."
Jiang Yuan interrupted Liu Jinghui and said: "I mean, pastrami can be made very delicious, and smoked chicken cannot be compared to it. The American-style Texas pastrami made by my father at home tastes very good.
, use a large American oven, start cooking in the afternoon the day before, put on firewood to smoke all night, and then start eating at noon the next day, the fiber of the beef has melted away, and the fully cooked beef has a lot of gravy..."
"Wang Chuanxing, bring the map." Liu Jinghui turned to call.
Wang Chuanxing held up a big map with excitement. He put it in the trunk when he went out.
Liu Jinghui took Jiang Yuan to find a deserted restaurant, put several tables together, and started drawing on the spot.
"Let's make the first picture first, with the transaction location as the center and a radius of six kilometers as the limit. In fact, 3 kilometers is about the same." Liu Jinghui said as he began to draw the picture.
For detectives with a reasoning style, criminal theories such as geographical profiling are basic skills that must be mastered.
The corresponding statistical conclusions are undoubtedly the cornerstone of the reasoning flow.
Just like Liu Jinghui said, the crime radius refers to the travel distance of criminals. A very simple understanding is that criminals actually tend to commit crimes in familiar areas, because crimes in unfamiliar locations not only increase the risk of exposure, but also waste
of the offender's time and energy.
Yes, criminals also spend time, energy and money.
How far is this travel distance? According to statistics, the average distance for crimes in most areas is within 3 kilometers. Specifically, the travel distance for violent attacks is generally shorter. Statistics from Sheffield in the UK are 2.4 kilometers, and the United States has a list of 2.4 kilometers.
Lexington is only 1.13 kilometers away. In comparison, pickpockets in Sheffield will go 4 kilometers away, and pickpockets in Dallas, USA, will go 9.66 kilometers away.
Similarly, the average travel distance for rape criminals in Washington is 1.85 kilometers, and that in Dallas is 6.28 kilometers; the average travel distance for robberies in Saint John, Canada is only 0.69 kilometers, while robbers in Washington are willing to travel 3.38 kilometers.
In terms of burglary, criminals in Ottawa, Canada are only willing to walk 0.56 kilometers, Dallas in the United States is 4.02 kilometers, Sheffield and Harrow in London are 2.95 and 2.98 kilometers respectively.
To sum up, Canadians are more home-loving and like to commit crimes within walking distance. The British are also very mediocre and rigid in crime. Even criminals are stuck with the world average and refuse to let go. Americans are the most bohemian and willing to go very far.
The place where the crime was committed, only when the rape happened, I felt a little impatient.
Liu Jinghui kept measuring the map with a ruler, then stuck the compass and started drawing lines.
Wang Chuanxing waited beside him, looked at it for a while, and asked: "I thought you could just draw a few 3-kilometer circles. Why are the sizes of each circle different?"
Liu Jinghui said while drawing: "Because the travel distance is not a straight line distance. The 3-kilometer circle you mentioned is equivalent to the shortest distance between two points on the map. This is the Euclidean distance, and the accuracy is too low. I measured it.
It’s the Manhattan distance, also called the taxi distance, which is equivalent to when you go from one place to another. You can’t walk the shortest distance in the air. The shortest distance you can walk on the ground or by car is called the Manhattan distance..."
Wang Chuanxing was also admitted to the criminal police detachment with high scores. He immediately recalled: "The hypotenuse of a right triangle is equivalent to the Euclidean distance, and the sum of two right-angled sides is equivalent to the Manhattan distance."
"That's what it means. So now you know why Euclidean distance doesn't work?"
"Because it is impossible for a criminal suspect to walk the shortest distance. At the very least, he has to walk the distance of Manhattan."
Liu Jinghui shook his head and said: "Because the Euclidean distance is Euclidean-Distance, or ED for short, ED will not work."
Wang Chuanxing shivered coldly.
Liu Jinghui's circles quickly filled the map.
The number of transactions made by Fourth Brother Li and others is very large, always dozens of times, and these transactions, whether it is Brother Li or the fat bag muscle, are recorded in accounts and time.
If you don't keep accounts, it won't work. If you don't keep accounts, you won't even be able to figure out the quantity and balance of the goods you received. If you talk about prices, shipments, etc. later, there will be problems, and you can easily be fooled by your subordinates.
Yuan Bomin and others finished their work and came to the restaurant to watch.
The pile of circles inside a circle created by the geographical portrait is relatively straightforward. At a glance, you can find that most of the circles intersect on three or four streets.
"Does the prisoner live near here?" Yuan Bomin was a little unsure. This seemed a bit too childish.
Liu Jinghui also shook his head and said: "The prisoner must be familiar with this area. But he does not necessarily live here. Criminals who commit crimes continuously generally have two modes. One mode is the mode of plundering nearby, that is, living here
The other is the out-of-home crime pattern, which is to commit crimes in places far away from home. The theory in this regard..."
"No matter what it is, the prisoner is likely to come and go here many times." Jiang Yuan interrupted Liu Jinghui's excitement and said: "Even if the people and goods are separated, even if the demolition house does not need to deliver the goods in person, considering the size of this case,
The dealer himself or his close associates must at least plan the location and route of each transaction, which requires visiting the locations in advance and becoming familiar with the local area."
"That's for sure. I think they have to come over in advance every time to take a look. Otherwise, the construction status of Wujia Pavilion may change after a while." Liu Jinghui agreed, and further said: "Say a bold statement
Presumably, I think the prisoner or the prisoner's cronies, the person responsible for transportation, must have a reasonable reason to travel here, work, study or live, at least have a pretty boy here."
"This can be used as a direction for follow-up screening." Jiang Yuan agreed tentatively.
"Then what?" Yuan Bomin asked impatiently.
Jiang Yuan stared at the map for a while, then pointed to a street a little to the east and said: "In this case, I think we can focus on collecting the surveillance of this street. Search the surveillance of the three days before and after the trading day.
Come out and take a look."
"This street is the main commercial street." Yuan Bomin felt a little numb when he saw the location, and said hurriedly: "There are community shopping malls, restaurants, snack bars, and small shops on this street. There are too many people.
."
"It's not that difficult. It's much smaller than the few kilometers around Wujia Pavilion." Jiang Yuan smiled.
"Even so..."
"The prisoner must have some distinctive characteristics." Jiang Yuan comforted Yuan Bomin and said: "Think about it, a person who trades several kilograms or even ten kilograms of drugs each time, even if he does not deliver the goods himself, he
There must be some qualities in him."
"That's for sure." Yuan Bomin first agreed, and then asked: "Where do you want to start? I mean, for example, what are the characteristics?"
"For example... are you rich?" Jiang Yuan smiled and said: "The poor people on the street, those with a monthly income of less than 10,000, can be excluded first, and the working class can basically be excluded."
Yuan Bomin hesitated for two seconds and said: "I'm not doubting, I just want to say, can Fu see it?"
"Ordinary people can tell the difference between working-class workers and drug dealer-level rich people." Jiang Yuan babbled to Wang Chuanxing as he spoke, then pointed at Wei Shijin, who was strolling boredly by the wall, and said: "The lives of cows, horses and pandas