Chapter 131 On-site collection

Chapter 131 On-site collection

Longde Village, Longli County.

This is the largest urban-rural fringe area in Longli County, and it is also the corner with the most flexible local industries and the most abundant human resources.

In the corner, there is the place where the deceased was buried, a small scavenger house, and a small yard surrounded by various construction waste.

There are similar temporary buildings everywhere here, some are built a little more squarely, even trying to maintain the level of the farmyard, and more are sliding down towards the angle of the shack.

The deceased's scavenging hut was a slightly more upright one, and it was built on the edge of the county road. Not too far away from it, there were food stalls and farmhouses.

The relatively convenient environment for entry and exit is also the capital of the deceased who can survive by scavenging.

Because he was older and had saved some money, the deceased would usually buy some scavengers from his peers, making him an upper-class figure among scavengers.

However, the courtyard looks decent from the outside, but when you walk in, it turns out to be a mess.

Dots of blood could also be seen at the scene.

Jiang Yuan looked around and saw mostly flecks of blood.

The so-called throwing state is mostly caused by blunt weapons. The perpetrator attacked the victim with a blunt object, and the blood adhered to the blunt object. When the perpetrator swung the blunt object again, the blood would be thrown around.

The flutter-like blood stains are diffuse to a certain extent, and the blood stains themselves are relatively consistent in size.

A small scientific experiment can help you see the flutter-like blood stains. Find a stick, take some bananas, mash them, add water and an appropriate amount of flour, stir evenly, and it will be like blood. You can use it. I dipped the stick in the sticky substance and swung it, and saw the fluttering blood stains.

Looking at the traces of blood, you can see the process in which the old scavenger was hit with a blunt instrument. It should have been many times. The cause of his final death should not be separated from it.

"The blood has been sampled. But it can be done again." Wang Lan said when he saw Jiang Yuan paying attention to the blood stains.

The grassroots police don't pay much attention to blood stain analysis, because they don't actually need to pay attention to the process of the deceased being beaten or killed. What they want is information about the murderer, preferably straightforward DNA or fingerprint.

Just as Jiang Yuan and others are doing now.

In fact, everyone does not know whether the murderer left fingerprints and DNA clues, but for this hope, a lot of manpower and material resources will be invested in searching.

Domestic criminals generally like to use stupid methods to solve the problem. Perhaps the manpower and material resources given are too sufficient, so that the most hard-core and even the stupidest methods have become the mainstream mode of solving the problem.

For example, investigation, such as DNA and fingerprints of all employees, etc.

This is unimaginable in European and American countries. Some countries in the Anglo-American system will not allow residents of a community to do universal DNA and fingerprints.

However, with the domestic response that murder cases must be solved, as in this case, after the DNA testing materials are collected, if the suspect cannot be found, it may be necessary to conduct DNA testing on all residents in the nearby urban-rural fringe area.

Even if the effect is not ideal, I will still do it.

However, this stupid method is also a guarantee to improve the success rate of murder cases. The domestic crime detection rate is extremely high in the world.

Jiang Yuan did not need to explain to forensic doctor Wang how his blood stain analysis was.

In fact, he just looked at it and was able to give a certain description of the state of the crime scene in his mind.

In Jiang Yuan's mind, the old scavenger was beaten continuously after being injured, and he hid in the hope of avoiding the attacks.

It was during this process that the shelves he stood in the courtyard were constantly being knocked apart and falling.

These racks were installed by the old scavenger himself. They are mainly a combination of wood. There are also semi-finished products such as wardrobes and open hangers used in clothing stores.

Anyway, the old man remodeled it and filled it with various items, the most common of which were clothes.

And all these things are now scattered in the yard, some are stained with blood, and some may contain the murderer's DNA.

A local criminal police officer from Longli County came over and saw Jiang Yuan's attention on his clothes, so he said to Jiang Yuan: "Today's waste textiles can be sold for a lot of money, but the recipient's requirements are relatively high. It usually requires a certain amount within a certain period of time. If the old man’s physical strength is not good enough, he has to save up and sell them together.”

Jiang Yuan nodded slightly: "I thought there would be a lot of wrapping paper and the like."

"That's hard currency from the scavenger trade. The old man put it in the house." The detective said and opened the small room inside.

It is still a self-built house, so the height is very limited, at most two meters. The bed used inside is also in the form of an earthen kang, which is probably a craft learned by the old man who scavenged when he was young.

The most abundant items in the house were cardboard, some metal, and a small number of daily items.

"We need to collect DNA from the house, but the priority is the crime scene now." The criminal policeman said, looking at Jiang Yuan, and said kindly: "Forensic doctor Jiang is very involved. I know you are very busy, and the work of this county and the province is also very difficult." A lot, this guy is really overwhelmed, so he asked for help."

Jiang Yuan said politely: "We should help each other."

"That's what I said, but this time we said we were asking for help. We specifically said that we hope to ask for help from Ningtai County." The criminal policeman introduced himself: "You may not remember, but you also helped us crack the case through fingerprints. A backlog... I took over at that time."

"It's so fateful." Jiang Yuan remembered the fingerprints in Longli County when he first started doing fingerprints. "

The detective nodded and whispered: "I am Zheng Xiangqian from the heavy duty team here. I am directly responsible for this case. If you need anything, you can come to me directly. This time, do you want to take fingerprints or forensic evidence? All is OK.”

Zheng Xiangqian handed a business card to Jiang Yuan.

Strictly speaking, collecting DNA evidence is not the job of a forensic scientist, but the job of an on-site investigation technician.

However, in the police station of Qinghe City, the technicians who do the current investigation are too basic. In terms of the level of detail of the DNA analysis alone, they may not be as good as the forensic doctors.

Jiang Yuan's fingerprint ability may be more trusted by the criminal police.

Jiang Yuan put away Zheng Xiangqian's business card, added the other party's WeChat ID, returned to the yard, and asked: "Um...how tall is the victim?"

"Relatively low, about 1.5 meters. He looks a little stooped." Zheng Qianqian was about to leave, but now he stopped and asked, "What do you think?"

"Don't use you, it sounds weird." Jiang Yuan said something, and said: "I thought that when the victim was beaten, it would be possible to knock down the things on the shelves if they were at the right height. If you hit the murderer at the corresponding location, it might be easier to extract DNA?"

"That's true." Zheng Xiangqian nodded in agreement, but didn't express much.

Jiang Yuan saw it and asked, "Has anyone mentioned it yet?"

"Yes." Zheng Xiangqian said: "We focused on extracting DNA from these items in the early stage, but we were also worried about incomplete extraction, so this was also a factor in applying for support."

If it is an ordinary item, it is actually relatively simple to extract DNA, especially the items in household lockers. Usually there should not be DNA on them, because after being stored for a long time, the activity of the DNA left in the front will be lost. .

Even if there is DNA, it should first be the DNA of family members. When encountering the DNA of other people, you should pay more attention.

But the old scavengers all picked up things, many of which were clothes, which made the DNA on them very confusing.

Moreover, unlike what most people think, all the DNA can be extracted by placing a piece of clothing in front of the examiner.

In actual DNA extraction, you still need to select a small spot, wipe it or cut it directly from the clothes, and then enter it into the DNA laboratory, and it is not immediately possible to match it.

There is a very critical step here called purification. It is necessary to select specific DNA fragments for amplification.

In short, to test all the DNA on a piece of clothing, you need to sample the clothes bit by bit, hundreds or thousands of times is not too many, and a few dozen times is not too few. Even so, there is a chance that some DNA may be missed during purification and other stages.

But no matter what, the more DNA extracted, the better.

Jiang Yuan followed Wu Jun and gave priority to items with blood stains.

Most of these blood stains belong to the victim, but if not all are preserved, some may belong to the murderer.

As we all know, hitting someone, especially beating them to death, is still very likely to hurt yourself.

Jiang Yuan also made full use of the ability of blood stain analysis to try to find some clues.

This is not easy, it can even be said to be very difficult.

This crime scene, despite its small size, is more complicated than four or five ordinary crime scenes in terms of complexity.

Jiang Yuan, Wu Jun and others quickly fell into a vast sea of ​​things.