Chapter 272 Shrinkage Rate

Chapter 272 Shrinkage Rate

There is a big difference between the burned bones and the original fresh bones.

Jiang Yuan took out the first bone from the evidence box. It had been burned to the point of porcelain, and the curvature of the bone surface had disappeared. Moreover, the bone was stained with several small bone fragments, many grains of coal residue, and unknown types of Small nodules formed by dissolving inorganic substances.

At first glance, this bone looks more like a strange handicraft, but if you look closely, you can see many details that belong to the bone.

As a forensic doctor, Jiang Yuan can see more. For example, this is a skull bone. The white color of the bone fragments is caused by burning at a high temperature of more than 1,000 degrees...

The organic matter on the bones has also been burned away, which means that the commonly used DNA technology has become ineffective.

Jiang Yuan took out the second bone without saying a word.

The degree of cauterization of this bone is slightly lower, it is about as if it has just been carbonized, and it is not yet at the level of porcelain.

But still, all the organic matter was burned away, and DNA methods were useless at all.

Jiang Yuan looked at the remaining dozen bones one by one and found that they were all in similar condition.

The difficulty suddenly increased, which meant that traditional DNA and other technologies were of no use at all. The only thing we could rely on was the most traditional forensic anthropology.

On the bright side, the bones in many graves, or massacre bone burial sites, are also of poor quality.

When it comes to difficulty, traditional forensic anthropology has always been extremely difficult.

There are too many inconsistencies, too many experiences, too many regression formulas, there are many things that cannot be understood by normal reading, and even the author cannot explain clearly, and one must have a master-disciple inheritance to understand.

This is like describing the feeling of snot sticking to the back of the hand, the feeling of tears smearing on it, the feeling of rice smearing on it, the feeling of water shield soup smearing on it, and the feeling of smearing beef soup on it.

Although human vocabulary is very rich, it is basically impossible to accurately describe the touch, or even to correspond one to one.

Forensic anthropology originally faces these things.

How does fresh bone feel, how does burnt bone feel, how does skull feel different from facial bones, how does finger bone feel different from toe bone...

Because forensic anthropology is originally faced with these seemingly simple and extremely detailed knowledge, without the teacher's step-by-step guidance, it would be very, very difficult.

As far as Jiang Yuan knows, there are two well-known veteran forensic doctors in Shannan Province, and they are often borrowed by ministries and commissions, used by provincial departments in other provinces, or traded out by leaders of their own city or county bureaus.

If forensic medicine is relatively scarce at the county level, then forensic anthropology medicine is very scarce across the country and even the world.

It mainly refers to the work done well, and the ones with two knives are not counted.

Jiang Yuan opened the forensic report made by the forensic doctor in Changyang City and looked at it carefully. He mentally graded it and estimated that this person's forensic anthropology ability was about 8 to 2.

The knowledge reserve is approximately at the level of 320 Wang Zhong.

This is already a very strong forensic medicine. Jiang Yuan estimated that it was probably 2 from Shannan Province who did it.

Jiang Yuan turned over the top of the forensic report, and sure enough he saw the name of the evaluator written on it: Zhang Fengtian.

Jiang Yuan couldn't help but said: "Forensic doctor Zhang has already done the appraisal, so there is no need for me to look at it again."

As he spoke, he picked up the bone and read it a second time.

Yu Wenshu saw Jiang Yuan's duplicity and said: "Forensic doctor Zhang gave an identification report, but it only confirmed that they were human skeletons. We don't know the gender, age, or height. Our current main investigation direction is , is an incinerator that can reach temperatures above 1,000 degrees. We have visited many places, but there are no clues..."

Although corpse burning eliminates a large amount of evidence, the process of burning corpses actually creates new clues.

For example, the method, technique, equipment, fuel, etc. of burning corpses are all problems.

Completely porcelain bones require a high temperature of more than 1,000 degrees, and carbonization requires 800 degrees. From 800 degrees to 1,000 degrees, it is just a hurdle that ordinary civilian furnaces cannot reach.

Jiang Yuan nodded as he listened: "There are only skulls, sternums and vertebrae here. It's really not easy to judge gender, age and height."

Yu Wenshu was a little disappointed, and then said: "The coal blocks above, or the hardened particles, have been extracted by the micro laboratory, but there is no result yet."

He actually expected Jiang Yuan to play some role outside of forensic medicine.

After all, most of Jiang Yuan's ability to solve crimes was actually outside of forensic science.

Jiang Yuan roughly guessed Yu Wenshu's mood, and said nothing or expressed it.

Solving a crime is different from many things. It doesn't mean you can do it just by following the leader's expectations or following the imagination of most people.

The kind of detective where I have an idea and all I need is a "CSI team" to solve the case.

"Forensic Doctor Zhang's forensic report is actually quite detailed. The upper edges of specimens No. 5, 6, and 7 are slightly higher than the middle, and they are all considered to be vertebral fragments. Among them, No. 6 has an incomplete transverse process hole on the posterolateral side of the vertebral body. , it was judged to be the cervical spine, and labial edge hyperplasia could be seen..."

Jiang Yuan commented, and then said: "Let me see, this is the vertebrae. The victim has cervical spondylosis, which is a little serious... It's a pity that there is not enough for screening."

Modern people, who does not have a little cervical spondylosis.

However, when it reaches the level of hyperplasia, it at least indicates that it is relatively old.

Wan Baoming said: "Maybe we can start from 30 years old?"

"That won't work." Yu Wenshu categorically objected: "I'm not afraid of a larger scope of investigation. What I'm most afraid of is missing something again."

Jiang Yuan asked: "What kind of investigation are you doing now?"

"One is a missing person and the other is an incinerator, but there are no results." Yu Wenshu sighed: "Now we can't even identify the victim."

If the victim is identified, the case may be solved through the victim's social connections, just like the 513 case just solved.

If the task force at that time had not been confused by the highly suspicious pattern of random killings and had changed the direction of investigation, they would have been able to unearth the murderer through the interpersonal relationships of the deceased.

Of course, no matter which one, it is very difficult.

The case in front of me is the same. It's just a few bone fragments. If you want to find the murderer, it will almost certainly be a process of finding a needle in a haystack.

What Yu Wenshu asked for was actually just to demarcate the area of ​​​​the sea.

You can make the sea area larger, but it must be as large as human power can achieve. Moreover, it must be to the extent that the manpower of the Changyang City Criminal Police Detachment can achieve.

"I have to study it carefully for a few days. I can't come to a conclusion now." The answer Jiang Yuan gave was a bit beyond Yu Wenshu's expectations.

"Uh... just a few bones, do you need to study them for several days?" Yu Wenshu hesitated.

The former forensic doctor Zhang Fengtian actually only looked at so many things for a day or two. After looking at them for a long time, is it possible that he can see the flowers?

Jiang Yuandao: "Because there are very few bone fragments, the information that can be given is limited, and most of the conclusions have actually been drawn by Forensic Doctor Zhang. The key now is how to decipher the subtle information to provide more detailed information." Lots of information…”

Yu Wenshu nodded. In this way, Jiang Yuan's thinking was really clear.

Jiang Yuan continued: "There are vertebrae and sternum. Logically speaking, the age and height should be able to be judged, and the gender should also be judged. But this bone is burned too much. In the final analysis, the shrinkage rate is not known. As a result, forensic doctor Zhang was unable to make inferences."

Jiang Yuan looked at Yu Wenshu and said: "After the bones are burned, they will shrink. How much shrinkage depends on the shrinkage rate. At present, relatively few people have done research on the shrinkage rate. A foreigner named Herman has done it. , proposed that the shrinkage rate of bone-burning is between 8% and 14%, but he should have done it at 700 degrees. He has not done it at higher temperatures, and neither has anyone else."

"With the shrinkage rate, you can calculate the original size of the fresh bones. Then you can infer the height, age and gender. But it is not very accurate. It is best to make a regression equation directly from the burned bones..."

Jiang Yuan said, his voice slightly lowered.

This work is quite tedious.

Yu Wenshu was a little dumbfounded when he heard this: "What should we do?"

"Can you apply for a corpse? The one for experiments?" Jiang Yuan asked.

Yu Wenshu spread his hands: "Don't say I haven't applied. This kind of scientific research project will take a long time."

"That's right." Jiang Yuan sighed and said, "Then let me estimate?"

"An estimate?"

"I can estimate a value, but this value is not safe. Please refer to it for reference." Jiang Yuan has actually obtained a nearly correct valuation from the system, but there is indeed little research on this matter at home and abroad. Everyone The estimated values ​​are all different, and there are problems with which one is used and which one is not used.

This is also because forensic anthropology is too difficult, and disagreements have already begun to arise when we have only reached level 3.

In other words, in terms of this skill alone, the level of inheritance and development among forensic doctors around the world is not high.

When the conversation reached this point, dozens of people in the conference room could tell that Jiang Yuan actually had an idea, but it was risky to be unsure.

This kind of uncertainty and risk is not only a matter of solving the case and funding, but also involves the manpower used in the subsequent investigation.

Asking as few as hundreds or as many as thousands of people to work hard for your estimate, and the estimate turns out to be wrong, Jiang Yuan really cannot afford to bear this kind of responsibility.

At least Yu Wenshu has to make the decision.

Yu Wenshu understood what he heard, thought about it for a while, and said decisively: "Okay. You estimate, now we can only treat a dead horse as a living horse doctor. What is the conclusion?"

"I'll give it to you tomorrow at the earliest. I'll let you know when I've finished the calculation." Jiang Yuan said, holding the evidence box, taking a notebook, and went to the corner.