In recent years, the role of spot investigation has become more and more significant in the investigation of various criminal cases.
From a part-time job more than ten years ago, where any criminal police officer could show off his skills, it has now developed into a specialized department.
In particular, the criminal investigation detachments of various municipal bureaus have basically formed professional teams for spot investigation, and most of them have two sets of brands and one team for trace inspection.
This is the case for the Haizhou City Criminal Investigation Detachment. The on-site investigation and later evidence examination were completed by Liu Guodong and four others.
Of course, there are also some awesome criminal investigation detachments, with more than a dozen people for current investigation and more than a dozen for trace inspection. These are usually deployed at least at the provincial capital level.
Footprints are commonly extracted information in live surveys, and footprint analysis has gradually developed into a specialized discipline.
However, whether it is the public security university or the front-line criminal investigation detachment, there is an extreme shortage of talents in this field.
There are many reasons. On the one hand, it is unsystematic teaching, on the other hand, some skills are cherished by everyone, and on the other hand, there is limited room for career advancement.
There are people who are willing to teach, but not necessarily people who are willing to learn.
Compared with fingerprint identification, footprint analysis is relatively backward.
Therefore, it is relatively rare for Lu Chuan to obtain footprint analysis skills through the system, although it is only elementary.
However, even if he is a beginner, it can only be said that there are some things that Lu Chuan is not yet familiar with, but it does not mean that the skills rewarded by the system will be wrong.
Footprint analysis has many methods from measurement.
The first is to determine the virtual edge, a shoe print, and the center of gravity is concentrated in the palm.
But because human feet have arches, generally speaking, the middle of the shoe print has the lightest marks, and the soles and heels have the heaviest marks.
Then take the center of the sole of the foot as the center point. The further outward, the shallower the traces of the shoe print will be, and a virtual edge will be formed at the edge.
Shoes of the same size have different sizes of empty edges, which means different weights of the owners.
The greater the weight, the smaller the virtual edge.
Combined with the length of the shoe print, the height and weight of the owner of the shoe print can be calculated.
However, in this case, the shoe prints left by the suspect had irregular front and rear virtual edges, sometimes larger and sometimes smaller.
Although this difference is very subtle, it can still be measured.
This situation is most likely caused by the other party wearing shoes that do not match the actual number.
At the same time, the virtual edges on the left and right sides of the feet are also different.
In other words, the other person's shoes are not only longer than the actual size, but also wider.
Combined with the calculated weight from the length of the stride, the depth of the footprints at that time, Lu Chuan determined that the owner of the footprints was a woman.
I just wore a pair of men's shoes, one size larger.
No wonder we can't find the suspect. The gender is wrong. How can we catch him? !
After repeated calculations to make sure that his judgment was correct, Lu Chuan continued to speculate on the suspect's physical characteristics based on the shoe print data.
"The inner edge of the shoe print is slightly heavier and the outer edge is slightly lighter...the opponent has X-shaped legs."
"Excluding the influence of the virtual edge, the opponent's foot length should be 24.2 centimeters...the height is about 1.69 meters, and the weight is about 61 kilograms..."
An hour later, the suspect was marked in detail.
She is female, 1.69 meters tall, weighs 61 kilograms, aged between 32 and 37 years old, and has X-shaped legs.
"Ding"
"The basic task is completed. The host used the footprints to analyze the physical characteristics of the suspect in the robbery and assault case."
The moment Lu Chuan completed the calculation, the system's prompt for completing the basic task appeared.
Next, Lu Chuan opened another pile of information, which was all the surveillance information near the location of the crime at that time.
During the robbery period, a total of thirty-two people had their image information collected.
Of course, the suspect did not necessarily go through surveillance that collected portraits at the time, and this is just investigation data.
Lu Chuan opened the information and compared the portrait photos one by one.
Within a few minutes, Lu Chuan's eyes were fixed on a woman named Zhang Yan!
"Hey, it's you!"
Taking the woman's photo, Lu Chuan locked the door of the current survey warehouse and went directly out of the criminal investigation detachment.
"Lao Yang, are you here?"
Unlike Lu Chuan who was assigned to the criminal investigation detachment, Yang Lin was assigned to the police station after graduation and became a film police officer.
By coincidence, Zhang Yan lives in the area that Yang Lin is in charge of.
Huaguang Street Police Station.
Yang Lin poured tea for Lu Chuan and took Zhang Yan's information: "This person lives in a low-rent house. Let me check the information."
Given the relationship between the two, there was no need for politeness. Lu Chuan directly explained the purpose of his visit: "This Zhang Yan is a suspect in a robbery and wounding case last year. See if you can collect her footprints. If you can compare them, this long-standing case will be solved." ”
"No problem, you sit down for a while, I'll be back soon."
Although the work in the police station is complicated, it is relatively easy.
Generally speaking, most of the cases taken over by the police station are neighborhood adjustment, petty theft and the like.
Once eight types of major criminal cases occur, they must be handed over directly, and the police station usually only does some work to cooperate with the investigation.
Of course, this does not mean that the police station must not be able to investigate criminal cases. If some cases are not solved for a long time after being handed over, the police station can also apply to have them returned.
Of course, a murder case was impossible, and no police station went back to apply for a murder case.
Yang Lin, like Lu Chuan, came from a professional background, and most of the work at the police station was relatively simple for him.
Within two minutes, Yang Lin handed a stack of materials to Lu Chuan: "This Zhang Yan works in Anping Electronics Factory. She is raising a daughter as a single parent and has a paralyzed mother at home to take care of her. She is our registered target for assistance."
Help object?
Lu Chuan did not expect that Zhang Yan's family background was so poor.
"I just contacted the electronics factory. Zhang Yan is still at work. Do you think we should go now or wait until she gets off work?"
After looking through the information, Lu Chuan thought for a while: "Now, let's go directly to the electronics factory."
Twenty minutes later, Anping Electronics Factory.
The workshop supervisor brought Lu Chuan and the two to the workshop: "Comrade police, the one standing next to the work station wearing blue work clothes is Zhang Yan."
"Let's collect the footprints first."
This is quite simple. Lu Chuan brought a special footprint collection printing paper. He only needed to stand on the printing paper for a short time to complete the footprint collection.
When Zhang Yan stood on the printing paper, Lu Chuan carefully observed the other party's expression. He could clearly see that the other party was nervous, his fingers were even trembling slightly, and his face was a little pale.
With a secret sigh, Lu Chuan picked up the collected footprints and compared them directly with the footprints found at the scene of the robbery.
Like fingerprints, footprints are different for everyone.
If the two footprints can be matched, it can be determined that Zhang Yan is the murderer.
"Police...comrade...you don't need to look...that person is me..."
Just as Lu Chuan was comparing, Zhang Yan behind him confessed in a trembling voice.
Criminal Investigation Detachment.
Qin Yong stared blankly at Liu Guodong who was reporting to him: "Will you say it again?"
Liu Guodong also looked confused: "Lu Chuan just called. He said that at the Huaguang Street Police Station, the police there caught the murderer of the robbery and wounding case last year."
