The difficulty in solving the unnamed corpse case is mainly because it does not know the identity of the victim, cannot investigate his social relations, and cannot analyze the causal relationships that may be related to the case. Without eyewitnesses, on-site evidence and other clues, it makes people confused and do not know where to start.

12.26 The identity of the victim in the case is clear, the scene of the crime and the scene of the body being thrown out is clear, and there are even weapons left by the suspect after the crime. Logically speaking, it should not be difficult to investigate, but the result is no clue.

The possible existence of the suspect's bloody handprints and DNA cannot escape from the murder weapon. The most urgent task is to determine the direction of the investigation, find out the causal relationship that may be related to this case, and lock in the suspect. At least the general range of the suspect must be bound. Otherwise, even if the murderer's bloody handprints and DNA are successfully extracted, the murderer may not be brought to justice.

After all, it takes a long time for the public security organs to establish fingerprint databases and dan databases for criminals, and it takes a long time to invest a lot of manpower and financial resources to complete the collection of basic information. If the murderer has no criminal record and does not commit another crime after committing the crime, then it is useless to have a database.

Confusing, the more you think about it, the more confused you become.

Han Bo rubbed his temples and raised his head suddenly: "Xiao Xu, you sort out the case from beginning to end, let's sort out the ideas together. If there are any omissions during the combing process, Lao Tian added. Political Commissar, Su Da, if you have any questions, you can ask them at any time."

"yes."

Xu Bing walked to the white blackboard, picked up the pen and started to sort it out. After four days of reading the materials, time, place, and characters, there was no need to read the notes, just like the owners.

"At around 4:38 am on December 26, 1990, Duan Qinglan, a sanitation worker in the port area, was cleaning the Huafeng Packaging Factory section of Changgang South Road, and found a female corpse in the trash can. Duan Qinglan was so scared that she threw down her tools and asked people nearby. Because it was not dawn, there were no passing vehicles or pedestrians on the road, she ran to the Changgang Road Police Station."

"Xiao Xu, wait, I have a question."

"Political Commissar, may I ask."

"Did the sanitation workers dump garbage into the trash bin, or did they find Xun Li's body when they were preparing to clean up the garbage in the trash bin?"

The facts proved that the idea of ​​sorting out the case was good. The lesbians were meticulous and thought of a question at the beginning. Han Bo knew what she really wanted to ask, and did not want to destroy this brainstorming analysis method, and listened with his chin.

"What I found when dumping garbage into the trash can, as for the garbage in the trash can, the male sanitation worker from the garbage truck is responsible for cleaning it. He shovels it on the truck with a shovel. The carriage is quite high, and the lesbians cannot do this job. They are mainly responsible for cleaning the road."

Zhou Suying was very surprised and asked: "Where is the first scene?"

Xu Bing took out a map of the time from his desk, hung it on a white blackboard, pointing to the location marked: "Here, about 280 meters away from the trash can."

“Where is the bike?”

"In the dead grass on the east side of the road, 6:3 meters away from the first scene."

Although Zhou Suying is not a criminal policeman and has never really participated in the case investigation, she has seen many criminal suspects, all of whom have mental problems, which is more dangerous than ordinary suspects.

At this moment, she was not the insider just now, but a policeman. She stood up and walked to Xiao Xu, pointed to the photo of the body on the white blackboard and said: "The murderer stabbed Xun Li several times, and it can be seen how much blood has been flowing from her clothes. The first scene was on the road, so far from the scene where the body was thrown, and there was no shortage of blood on the ground. The sanitation worker dumped the garbage into the trash can, saying that she had cleaned the road. Since she had cleaned, how could she not find any blood? If she found the blood, why didn't she be suspicious?"

I have never been a criminal policeman or seen a bloody scene, so it is normal to ask such questions.

Xu Bing put down the pen and explained: "Reported to Political Commissar Zhou, the blood flowing out of the human body will gradually change from bright red to dark red, reddish brown until gray. Forensic doctors speculated that the victim's death was about 9:00 to 10:30 on the 26th, which means that the blood has not only dried but also changed color.

It was not dawn when the sanitation worker cleared the road, and it was difficult to tell whether it was blood or other stains under the dim street lights. The police officer who took the transcripts at that time worked in detail and asked the same question. The materials showed that she did not pay attention at that time, and swept the broom all the way."

"She was the first to find a body and accidentally destroyed the scene."

Tian Guogang became addicted to smoking. He was afraid of choking the two leaders who did not smoke. He walked to the window and pointed it back and said, "The big broom splashed everywhere with small solidified blood clots. It could be found within 280 meters of the distance during the investigation site, which made us unable to determine whether the murderer carried the body over and threw it into the trash bin, or had used transportation."

Putting the body on a bicycle will cause blood to drip, and putting it on a tricycle will also cause blood to drip. The transportation he mentioned obviously refers to cars. In other words, they suspected the people attending the banquet at that time.

Is this right? How can you not check such a big doubt? At most, you are worried that the impact will not appear on the material.

Han Bo decided to ask them how they checked it later. Zhou Suying didn't expect this floor and asked a question that was very unsense. She felt a little embarrassed and returned to her seat to signal Xu Bing to continue.

"After receiving the call from Changgang Road Police Station, it immediately sent police officers to protect the scene and reported to the branch office. At 5:24 a.m., Wei Detachment, who was then the deputy director of the criminal investigation of the Port Branch, led the police to the scene. At that time, the branch office had no forensic doctors, so he could only ask for help from the municipal bureau, and organized criminal police and police station security police to visit and inquire.

At 7:17, the forensic doctor of the municipal bureau arrived at the scene and investigated with the technical police of the branch. When the forensic doctor arrived, the Wei Detachment had found the first scene, the murder weapon and the victim's bicycle. At about 8:00, an employee who lived in the dormitory of the Port Authority Bureau worked in the second factory of the Hong Kong Cotton Factory, recognized the victim while watching the fun...

The city leaders were furious and ordered the Municipal Bureau to be responsible for the case investigation. The then director personally served as the head of the task force. The deputy director of the Criminal Investigation of the Municipal Bureau, the head of the Criminal Investigation Detachment, the director of the Branch, and the deputy director of the Criminal Investigation of the Branch were all members of the task force. At that time, they were divided into three groups. The first group was responsible for investigating the social relations between the victim and the victim's husband, the second group was responsible for investigating the social relations between the victim and the victim's husband, and the third group was responsible for investigating the social relations between the victim before coming to Nangang."

Xiao Xu paused and then said: "The second group is personally responsible for the deputy director of the Criminal Investigation of the Municipal Bureau. This group is divided into several groups. The first group is responsible for investigating all adult men within 3 kilometers around the crime scene. The second group surveys all the criminal personnel in the city. The third group visits and inquiries about hotels in all sizes in the city. The fourth group investigates all ships leaving the port before and after the incident. The fifth group surveys the migrant population in the city.

Almost all the police force that can be taken into account in the city was almost all the time to suppress this case. During the investigation, more than 100 cases of big and small were destroyed, and more than 200 suspects of various types were arrested, so that many citizens thought they had begun to crack down again..."

Although Nangang is one of the first batch of open coastal cities, its economic development speed is not fast compared to several open cities in Dongguang, and there was not much migrant population at that time.

Since the incident was Christmas in Western countries, there were no external ships docking here, and there were only a few domestic freighters at several wharfs. The passenger terminal was in the Yangtze River area and was not in the port area where the crime was found. There were neither passenger ships docked in the middle of the night, and even if they came from the passenger terminal, they would not be close.

The locals commit crimes, at least the permanent local personnel are extremely likely to commit crimes, but they just failed to find out.

The more than 100 photos on both walls are all people who thought they were a little suspicious at the time.

This suspicion does not mean that they are more likely to commit crimes, but they have criminal records or are idle. There are no absent certificates on the night of the incident, or the absent certificates provided cannot be confirmed. At least 90% of the more than 100 people do not know the victims, and there will be no intersection between work and life circles.

In the survey, the case was handled in a row and the court was in question.

Han Bo walked to the corner of the wall and squatted down. While listening to Xiao Xu sorting out the case, he looked through the victim's relics.

After Xiao Xu finished speaking, Lao Tian added.

He looked back at Han Bo and whispered: "There was no progress in the investigation and the social relationship between the victim and his wife failed to find out the results. We proposed that those who attended the wedding should check it. There were so many city leaders involved, and the bureau leaders did not agree or explicitly objected. The Wei Detachment organized us to conduct an investigation from the side.

First, ask who are at the wedding, then ask indirectly how they got home. Take a car and ride a bicycle with relatives and friends to go back is equivalent to absenteeism. The suspicion can be basically eliminated. If you can't find out, or if you go back, it will be a key investigation."

"Old Coach" did not disappoint, Han Bo secretly praised one.

Zhou Suying felt it was incredible and couldn't help asking: "Lao Tian, ​​so you checked me back then?"

"No."

The political commissar of the Technical Investigation Detachment, the highest female cadre in the city's public security system.

Not to mention not checking her, even if she was checked, she couldn't say it. Tian Guogang hurriedly explained: "The murderer stabbed the victim four times and stabbed him in several layers of clothes. He was clean and neat. The woman was not so strong. We only investigated the adult man secretly, and even secretly checked the car the leader was riding, but found nothing."

"What happened later?"

"I was discovered later. When I investigated a driver, I couldn't implicate the leader. I took the initiative to admit my mistake, but I was still implicated."

The case was not solved, and he actually secretly investigated the leader!

Investigating the city leaders is not a trivial matter. Han Bo finally figured out why the then bureau leader stepped down.

The reason why the "old coach" was able to be the captain of the criminal police detachment was that his level was not high enough at the time, and his subordinates helped him cover him. The city leader who was on the fire did not notice him, otherwise he would probably be a police officer in a police station now.

No wonder no one mentioned this case for a long time, it turns out that there are so many hidden stories.

Han Bo was filled with emotion and didn't know what to say. Su Haibing looked up and said, "Han Detachment, in the past ten years, we can only find the old comrades from Hong Kong Cotton Factory No. 2 and the Yangtze River District Cultural Bureau to understand the situation. We can only go to the victim's school to check his classmates and find a few students who can contact to learn about her situation during her college and high school."

"I think so too."

"When will the dagger be tested? If fingerprints and DNA can be detected, we will at least have a clear idea in the next investigation."

If it cannot be detected, it means there is no evidence. Even if the causal relationship that has not been discovered before was discovered during the subsequent investigation, it will not be able to bring it to justice if it is successfully locked up.

He doesn't want to do useless work, and Han Bo doesn't want to do either.

"Blood handprints are a common trace at the scene of murder cases. After years of practice and research, the trace inspection technicians have summarized many effective methods, but there are common problems such as insufficient application scope, the lines of the handprints are prone to diffusion and damage, and the dark object shows that the handprints are weak due to background interference and contrast.

Since the New Year, I have started to study how to make possible fingerprints on the tip of the dagger appear. I have read many documents and consulted several experts on the display of blood fingerprints. There are several ways. The key is that we can only succeed but not fail. We must be based on the premise that we can make timely remedies after the display failure.

For this reason, I went to the Red Cross to buy a bag of blood. The way was to prepare more than a dozen test materials on the metal with fingerprints, order several reagents according to the test plan, and wait until the metal is rusted for a period of time before conducting the test."

"Do you have to wait?"

Han Bo nodded and explained: "The old blood marks, the peroxidase in the blood loses its activity and cannot participate in the reaction, but the iron ions on the hemoporphyrin ring in the hemoglobin molecule can act as a catalyst, which can release primary ecological oxygen by hydrogen peroxide, oxidize the colorless tetramethylbenzidine into tetramethylbenzidine blue, showing a blue-green blood mark.

It is similar to last year to take a few days to extract the DNA on the lightning tube. It can only be carried out after the peroxidase in the blood of the test material is inactive. It is confirmed that the test is successful, the color contrast is obvious, the lines are coherent, and it is easy to take pictures. If the test fails, you can use the second set of solutions to remedy it before I can test the weapon."

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Chapter completed!