Chapter 1158 They are different
"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 When it comes to applying theory to relevant 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 spatio-temporal 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 without you Such 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 go 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 his superior unit and uses these criminal theories to solve cases, he will still be regarded as a scholar. The cooperation between various units should be somewhat slack. If the tasks are too heavy, some people will say strange things in person. It is common for things to go wrong when things go wrong.
Jiang Yuan nodded as if he understood.
Liu Jinghui looked at his dragon's confused look and couldn't help but sigh: "You can't imagine something you haven't seen before!"
"Geography has indeed great restrictions on people. People are prisoners of geography." Jiang Yuan nodded in agreement. People from the north who have never seen the sea can hardly imagine the rough waves during a typhoon, and people from the south who have never seen snow can hardly imagine the cold when water turns 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 - just like, people like you who have a ranch at home , I can’t imagine what weird things some people would do 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. 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 it in the afternoon the day before, put on firewood to smoke it all night, and then start eating it 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 large map in his hands. He had 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 map first, with the transaction location as the center and a radius of six kilometers as the limit. How about it?
In fact, 3 kilometers is about the same. Liu Jinghui said as he started drawing.
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 the crime radius mentioned by Liu Jinghui, it refers to the distance traveled by the criminal. A very simple understanding is that criminals actually tend to commit crimes in familiar areas, because committing crimes in unfamiliar locations not only increases the risk of exposure, but also wastes the criminal's time and energy.
Yes, criminals also spend time, energy and money.
How far is this travel distance? According to statistics, the average crime distance in most areas is within 3 kilometers. Specifically, the travel distance for violent attacks is generally shorter. According to statistics from Sheffield, UK, it is 2.4 kilometers.
Lexington in the United States is only 1.13 kilometers away. In comparison, pickpockets in Sheffield will go 4 kilometers away, and pickpockets in Dallas, the United States, will go 9.66 kilometers away.
Similarly, the average travel distance of rape offenders 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 moderate 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 far away to commit crimes. Only when it comes to rape, they can't wait.
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 by air. You can walk on the ground and the shortest distance by car is called the Manhattan distance..."
Wang Chuanxing was also admitted to the criminal police detachment with high scores, and 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, abbreviated as ED, E
D will not work. "
Wang Chuanxing shivered coldly.
Liu Jinghui's circle 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.
It's impossible not to keep accounts. If you don't keep accounts, you won't even be able to figure out the quantity and balance of goods 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 the circles created by the geographical portrait is relatively straightforward, and everyone can spot it at a glance.
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 dramatic.
Liu Jinghui also shook his head and said: "The prisoner must be familiar with this area. But he may not necessarily live here.
Criminals who commit crimes generally have two modes. One mode is the nearby plunder mode, that is, people who live nearby; the other is the out-of-home crime mode, that is, they deliberately go to places far away from home to commit crimes. theory."
"No matter what it is, the prisoner is likely to come and go here many times." Jiang Yuan interrupted Liu Jinghui's excitement,
Said: "Even if people and goods are separated, even if the big demolisher doesn't have to deliver the goods in person, given the size of this case, the big demolisher himself or his close associates must at least plan the location and transaction route of each transaction. This requires Visit the locations in advance and get 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 Presumably, I think the prisoner or the prisoner's cronies, the person in charge of 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 five-kilometer radius of 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 will There will definitely 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 - rich?" Jiang Yuan smiled and said: "The poor in the entire 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 people and drug dealer-level rich people." Jiang Yuan said to Wang Chuanxing, then pointed to the Wei Shi title who was strolling boredly by the wall, and said: "The living conditions of cows, horses and pandas , naturally it’s different.”