Attending ex-girlfriend's wedding, arresting the groom's officer on the spot

The preservation time of skeletons is closely related to the surrounding environment.

Human corpses are not protected by fur. In an external environment of high temperature and humidity, the corpse will start to decay significantly in about a week.

Under normal circumstances, after a month or so of a corpse exposed to the wild, the skin, muscles, etc. will rot away, leaving only the fascia.

It takes about two months for bones to turn into white bones. Human bones can be kept for at least one year when exposed in the wild. However, if the conditions are suitable, they will generally decay within 5 years without leaving any traces. disappear.

Bodies buried underground will decompose slower than those on the ground.

Because the oxygen underground is relatively scarce, some oxygen-loving bacteria are not active frequently, which will cause the corpse to decay relatively slowly.

The specific decay time depends on the soil moisture and temperature.

Generally speaking, it takes about one to three years for a corpse buried underground to completely turn into bones.

Of course, there are some special circumstances, such as the underground humidity is very high and the water content is very large, the body may not completely decompose.

Even if it takes a relatively long time, three to five years or even more than ten years, the corpse will not completely turn into bones.

The soil moisture and temperature under the Lion Rock Bridge are relatively normal. The corpse will become skeletal after being stored for about a year. In 20 years... some small bones have completely disappeared, leaving only some large bones.

And apart from some hard and larger valley bones such as leg bones, tibias, hip bones, and skulls, some other bones have become relatively fragile.

As for the bone grafting and foot bones of the palms and soles, there is basically not much left.

The excavation of bones this time took longer than the time after Wang Mingshan's body was discovered yesterday.

Lu Chuan and Lao Bai worked on it for four or five hours. When it was almost dawn, they finally completed the cleaning work of the 20-year-old skeleton.

Others were not idle either. Wang Changjiang and Shen Yan were summoned to the scene overnight to be responsible for sorting the other skeletons and transporting them later.

Seven skeletons...

The analysis and identification alone can be completed in one or two days.

It was already 10:30 noon when all the skeletons were transported back to the Criminal Investigation Detachment.

Forensic autopsy room.

Lu Chuan yawned and discussed with Wang Changjiang how to carry out the work.

Wang Mingshan's skeleton has been identified and analyzed, his identity and skeletal characteristics have been confirmed, and the corresponding identification and analysis report has also been completed.

For the remaining skeletons, the most important thing is to determine their identities.

This time, because there were too many bones, the forensic doctors and investigators decided to join forces.

"It is better to collect DNA information identification samples first and see if we can compare the identities of these people through the DNA information database."

There is nothing wrong with Liu Guodong's suggestion.

Perhaps because it was so long ago, the clothes on these corpses had already rotted so much that it was impossible to identify them.

The remains of ID cards were found on two corpses, but the words had long been blurred, and the ID cards themselves were rotten and almost gone.

That is to say, from this point of view, the other party did not consider concealing the other party's identity when killing people or burying corpses.For example, next to Wang Mingshan’s body is his police officer ID.

Collecting DNA information identification samples from skeletons is much more difficult than collecting general DNA information identification samples.

Theoretically, as long as there are cells with nuclei, DNA information identification can be carried out.

However, extracting DNA identification information samples from skeletal bones has always been a difficult problem in the field of DNA information identification.

The most difficult thing is to extract the DNA samples from the bones. The detection method after successful extraction is not unique.

Currently, the more mature detection and extraction methods are mitochondrial DNA detection, str detection and ngs detection.

Judging from Lu Chuan's current ability in the intermediate field survey skills, the probability of successful identification of DNA information samples extracted from long bones such as tibia, fibula, and femur is relatively high.

DNA testing samples extracted from some smaller bones such as the soles of the feet and the palms of tambourines are the most difficult to successfully identify.

In fact, from the perspective of forensic anthropology, after the bones are discovered, the first thing to be identified is to determine the species of the bones.

Just like the work after discovering a blood stain, you must first determine whether the blood stain is a blood stain. If it is determined that the blood stain is a blood stain, is the blood stain a human blood stain or the blood stain of another animal?
The same is true for bones. Once you have determined that the thing you found is a bone, you need to identify and analyze the species of the bone. Is it a human skeleton or the bones of other animals?
The Haizhou City Criminal Investigation Detachment encountered a similar case more than ten years ago. After the criminal suspect killed a person, he burned the body, leaving the skeleton, which was mixed with the bones of other cattle, sheep, chickens and so on.

There are also older ones, which are more difficult to identify.

Most people take it for granted that human bones are very different from those of other animals, but this is not the case.

One refers to a human finger bone and a pig's foot bone. Most people can't find out what kind of animal bones or human bones these bones are.

Everyone knows the skin and flesh, but the bones...

Even professional forensic doctors like Wang Changjiang and Shen Yan are not particularly familiar with human bones.

In the criminal investigation profession, there is a special category of skeletal identification and analysis.

The reason for this situation is also that skeleton cases are generally relatively rare.

After confirming the plan, everyone started busy. Liu Guodong and Lao Bai Yangsen were responsible for polishing and cutting bone fragments.

Lu Chuan numbered the Qiju skeletons one by one, and then conducted identification and analysis on the skeletons one by one.

"Skeleton No. 1, male, aged between 38 and 43 years old, about 1 meters tall, with two dental implants on the left upper jaw..."

Skeleton identification and analysis may be difficult, but it is not difficult at all. The key point is that you have not mastered the trick.

With Lu Chuan's current eyesight and touch, after touching the bones, he could determine some basic information about the owner of the bones after another 10 minutes of observation.

The reason why we need to touch is because the bones of people of different ages, genders, and even different occupations feel different to the touch.

"Skeleton No. 2, female, aged between 42 and 46 years old, about 65 meters tall, with no history of childbirth."

This judgment attracted the attention of Wang Changjiang and Shen Yan. There was no history of childbirth between the ages of 42 and 46?

"The two skeletons were found in a corpse pit. I suspect they may have known each other before their death, or had a very close relationship, such as a couple."

"Brother Bai, will we check later to see if a couple disappeared eight years ago?" (End of Chapter)