"The iron chains are tied here," Yang Qiuchi pointed to the bottom of the pillar, took the kitchen knife and made a chopping move, and said, "If it were you, you would use this hatchet to cut off the iron chain, how would you cut it?"

Song Yuner took the hatchet and looked at the pillar: "Of course, this pillar is used as a cushion, press the chain on the pillar and cut it diagonally."

"From the point of view, it was cut by one knife. If you cut according to your method, there will definitely be cut marks on the pillar. At least there will be indentations on the pillar wood being hit by the hatchet. But if you look carefully, there are only marks of left and right friction on the pillar. This is the one left behind when the dog pulls the iron chain and rubs the chain, but there are no marks or indentations on the hatchet."

Song Yuner took a closer look: "It's just not." After thinking about it, she said: "That tall one was cut directly on the ground."

"You have a good look at the shape of the hatchet, especially the pointed tips that bent downwards in front. You can try to see if the chains placed on the ground can be cut off?"

Song Yuner competed and smiled: "I can't cut it, the elbow in front is supported, and the hatchet blade cannot cut the iron chain on the ground." Then she thought, and said: "But, can you find a piece of wood to cushion, isn't it enough?"

"Then look around, are there any wood used as a mat?"

Song Yuner looked around and saw that the yard was neatly arranged so that she could not see any wood used as a mat.

Yang Qiuchi said again: "Besides, isn't this pillar the best mattress? Isn't it much more convenient for people to cut thin iron chains with hatchets to cut them directly on the pillar?"

"That's right, there are neither mattresses nor cut marks on the pillars. It seems that this man did not use a hatchet to cut. So, what did he use to cut?"

"It's a very axe, so I'm going to focus on the investigation." Yang Qiuchi stood up and walked back to the pile of hatchets, in front of the axes, and instructed the yamen to bring the axes back, and put the remaining hatchets at Sulizheng's house to keep, and then return them to the villagers after the matter was clear. Then, he brought a team of people back to Mazhou City.

Although the choppers were initially lined up with only the axes left, there were dozens of axes brought back by the constables. There was no way, so they could only test them one by one to see if they could find the axes that cut off the chain.

To find out which axe cuts off the chain, trace identification is required.

The axes used by ordinary people are usually made of molds in blacksmith shops, and are poured from the same mold, so the new axes do not have very obvious characteristics. However, after using them for a period of time, they will constantly cut and polish them. They will form their own different blade characteristics.

The blade part of the chopper is similar to the naked eye. It is very sharp. As long as it is often polished, there will generally be no obvious curling. However, if you observe the blade with a microscope, you can find that the blade is uneven. It is precisely because of this characteristic that when a knife cuts an object, it will leave scratches that are difficult to distinguish between the naked eye on the cross section.

This kind of mark is very similar to the barcode in a supermarket, but it is generally impossible to distinguish the marks of human eyes and cannot be seen, and must be seen with a microscope. The scratches on the cross sections of objects cut by the chopper are the same as those of human fingerprints, and cannot be found in two cross sections.

Of course, this kind of scratch is still different from a human fingerprint. Because a human fingerprint will not change for life, even if the fingerprint is cut off with a knife, destroyed with sulfuric acid, or even peeled off this layer of skin, the fingerprints on the newly grown skin will still be exactly the same as yours, and the pattern characteristics will not change at all.

The cross-sectional scratches of the cutter are different. As long as the cutter is polished or used frequently, the characteristics on the cutter will slowly disappear and change. Therefore, if the cross-sectional scratches extracted by the criminal investigation department cannot find the cutter within six months, under normal circumstances, this data can basically be thrown away.

This case has just happened two days ago, so after analyzing and comparing the scratch marks of the cut and cut, you can find the chopper to form the cut and cut surface.

What Yang Qiuchi needs to do is to cut a certain item (usually a softer aluminum pole, which will not easily damage the cutting edge characteristics of the chopper). After forming a cut mark, stand and compare the cross-section scratches of the iron chain extracted from the neck of the deceased. If the characteristics can obviously overlap and the non-coupled parts can be reasonably explained, it can be concluded that the broken sample was cut off by this cutter.

To perform this kind of trace comparison, you must trust a microscope. The microscope that Yang Qiuchi brought through is a charge coupler microscope. It can be connected to a computer and transfer the images you see to the computer for comparison processing.

However, the blade part of the axe is of a certain length. You must find the blade part of the cutting chain and conduct a cutting sampling test to achieve comparison value.

The chemistry of the iron chain is definitely different from that of the axe, especially the steel part of the blade edge of the axe. Since the objects act mutually, the axe will break the iron chain and form scratches on the broken chain, and the iron chain will also react to the axe. It not only supports the curling of the blade edge of the axe, but also can rub and adhere part of the iron chips on both sides of the axe blade.

The simplest example of explaining this phenomenon is to use an axe to chop people's limbs, which will stick blood on the axe. Or use a knife to chop a crayon, which will rub the color of the crayon on both sides of the blade. However, if you use an axe to chop iron chains, the chain will generally not decolorize, so the scratches formed on both sides of the axe blade are generally invisible to the naked eye. How to find them?

If it is in the modern early value, it is very simple. Check the chemistry of the adhesions at the blade of each axe, and compare it with the chemical composition of the broken chain to be inspected. You can quickly find out if it is like an axe cutting off the iron chain, and you can also accurately determine which specific part of the blade of the axe cutting off the iron chain.

If further confirmation is required, you can use this part to cut the aluminum rod to form cut marks and compare them with the fracture. As long as the extraction is timely, the same determination can be made. Even if the characteristics of the axe blade have been destroyed for a long time, the same determination can be made based on the chemical composition of the adhesion of the blade and the iron chain fracture.

In modern forensic physical evidence testing with chemical inspection conditions, this is very simple. However, Yang Qiuchi brought the forensic physical evidence testing equipment to Tibet this time, there is no chemical inspection equipment, because chemical inspections vary greatly depending on the substance being tested. There is no need to build one of them if it cannot be exhausted.

Yang Qiuchi does not have a component testing equipment for taking a break, so there is no way to use this method to test it. He can only find other alternative methods.

What method should be used? The most urgent task is to find the part of the axe cutting iron chain, then conduct a simulation test to form a cut section mark, and then conduct a comparison and shadow detection. Finally, it is found which axe formed this fracture.

Although the iron chain is very thin, only the thickness of a silver hairpin, the iron is still relatively hard, and the hardness of the steel in the Ming Dynasty is obviously not as hard as that of modern times. Therefore, if you use an axe to cut the iron chain, the edge of the axe may be curled or collapsed. Now you can only conduct a simultaneous cut and cut test on each axe.

This kind of test is generally made of aluminum poles, but it was difficult to find this thing in the Ming Dynasty. Yang Qiuchi could only find a few thicker copper wires. The hardness of copper was much softer than that of iron. It was less likely to destroy the characteristics of the axe blade.

First check the edge of each axe to find the curling and collapsed parts. Use this part to cut the fine copper wire, then use the micro-hinged connecting the laptop to observe and extract the cross-sectional image, and then compare the traces with the cross-sectional image of the iron chain.

There are dozens of axes, and each axe has almost three or five curled or collapsed. After accumulating, hundreds of them need to be tested. It is really tedious. However, forensic examinations are originally very tedious and tedious, and they are even tiring after doing them for a long time. But Yang Qiuchi has become accustomed to them.

I was busy until dark and I only checked half of it. During this period, someone sent to Huo Xiaosi's grandmother's house to verify the situation. He said that Huo Shangsi's family was indeed there the day before yesterday and had never left Shou. Qin Wei and his neighbor could testify.

Huo Xiaosi's family had no time to commit the crime. It seemed that they could only continue to search for clues to the cutter from the broken mark.

Hong Ling came to ask Qiuchi to eat a bowl of rice. He hurriedly ate and ran back to continue the test.

Song Yuner asked him how the test was, and he was just vague. No one in the previous test found the same or similar marks as the iron fracture cut and scratch marks, and he did it for an afternoon of useless pull.

Song Qing felt sorry for him and told him not to work so hard, to have a good rest, and to continue working tomorrow.

Yang Qiuchi also knew that revolutionary work could not be completed. Besides, it is not considered a revolutionary work now. However, this is what he is like. Once the work begins, he doesn’t like to pause halfway.

So, after a quick meal, he returned to the forensic room to continue the test.

Until late at night, I was dizzy and only half of the test was detected. The table was filled with short copper wires for cutting and cutting the test site, but it was still not found.

Song Yuner came a few times. Yang Qiuchi's forensic computer prohibited anyone from coming in. The door was tied up from inside. Song Yuner called out a few times and said she wanted to come in and accompany her, but in the end, Yang Qiuchi still didn't open the door.
Chapter completed!