The bridge piers were demolished using blast-free demolition. Under the hammering of blast-free hammers, the cement block debris on the bridge piers were large and small.
The steel bars twisted and wrapped around the fragile bones.
Perhaps because the initial blast was too intense, the exposed left hand bones were partially shattered and incomplete.
Lu Chuan had been observing for a while.
"Mr. Zhang, you should first dig out the skeletons from the cement pier," Lu Chuan pointed to the nearby bridge pier: "When Team Qin just reported, he said that there are also skeletons in the cement pier next to it."
"On the other hand, let's see if we can first collect DNA information from the skeleton fragments to determine the identity of the deceased." ap.
Lu Chuan had experience in skeletal identification and analysis, and was affirmed by Zhang Yuanchao.
Zhang Yuanchao nodded: "In this way, let's collect some bone fragments and do some technical experiments first. The field investigators and forensic doctors in QZ City will also have to work hard to clean out the bones as quickly as possible."
The case is more important mainly because of the large number of skeletons discovered so far.
However, the specific investigation situation still depends on whether the identity of the skeleton can be confirmed first.
"I also collected some remaining pieces of clothing."
Lu Chuan made another request.
The impact of the case is great, but it is different from the investigation of ordinary cases.
The cleaning of bones is very time-consuming.
Normal violent demolition is impossible, otherwise, all the bones that will be cleaned up will be debris.
Of course, it is impossible to hammer it bit by bit. If you do it that way, it will probably take more than ten days to finish.
Li Donglin of the Provincial Department personally supervised the operation. Qin Hui, captain of the QZ City Criminal Investigation Detachment, came on the scene in person. Firefighters helped and started cutting the bridge piers bit by bit.
QZ City Existing Exploration Office.
Skeleton identification and analysis requires special instruments. The QZ City Criminal Investigation Detachment does not have the relevant instruments and can only send them back to the provincial department for processing.
But Zhang Yuanchao did not leave. Li Changgeng and the others could handle the technical matters. As long as the results were sent over, Zhang Yuanchao could analyze the necessary elements based on the results.
Lu Chuan was responsible for the investigation of the deceased's clothing fragments collected at the scene.
"There's blood!"
This is Lu Chuan's biggest discovery.
The clothes have been in the bridge pier for at least fifteen years. Because the cement blocks oxygen, they have not oxidized and are in a relatively good state of preservation.
After at least fifteen years of storage, the blood stains could no longer be red.
But the existence of blood stains will not disappear with the passage of time.
Even in many crime scenes, just washing with water will make the surface clean and there will be no red blood stains. However, using some on-the-spot investigation methods, blood stains can still be found relatively easily.
However, DNA and other information cannot be obtained from such blood stains.
As the head of the technical criminal police, Zhang Yuanchao summarizes all clues.
The technical identification data of the skeleton has not yet been released, and Lu Chuan's discovery is the only discovery.
"Can I do a blood type test?"
"Let me try." Lu Chuan's intermediate spot survey skill has technical reserves in this area, so there is no big problem in handling it: "The clothes fragments are relatively small, so it may not be possible to extract a sufficient amount of surface antigens."
"It's okay. Since there are blood stains, we might be able to collect them when more fragments are excavated at the scene."
Technical identification requires more than just instruments. Many things can be analyzed from the surface of the bones.
On the dissecting table, there are three left hand skeletons.
"Lu Chuan, what can you tell from these two left hand bones?"
The arms of the three left hands on the bridge pier are still in the bridge pier, but the left hand has been removed.
It's just that it's more severely broken, and there are some missing parts when put together, and some of it is wrapped in cement fragments.
Since five years ago, Zhang Yuanchao has seldom conducted forensic appraisals in person, but has guided his younger students to learn from him.
Therefore, Zhang Yuanchao mostly uses the method of asking questions to guide.
Forensic doctor Wang Ruiqing of the QZ City Criminal Investigation Detachment was still at the scene, and the people following Zhang Yuanchao came from the provincial department.
The metacarpal bone is a special skeletal component of the human body.
Both the palm and the sole of the foot have the largest number of bones. In comparison, the palm bones have more identification value than the sole bones in the forensic analysis.
The most important of these is the determination of bone age.
The degree of development of the ossification center between the phalanges of the metacarpal bones, the carpal bones, and the radius and ulna is a very important basis for determining bone age.
As it happened, the metacarpal bones of the three left hands were more severely shattered, but the integrity was pretty good.
The thickness of the ossification center can be better observed.
Of course, theoretical knowledge is theory, and every forensic doctor present knows this, but to what extent the ossification center has developed and what age it is related to, this is something that only experience can bring.
"Judging from the size, the two hand bones on the left are wide and the gap between the finger bones is larger. It is more likely to be male."
Generally speaking, male bones are wider than female bones, especially the hand bones.
The contrast between the three left hand bones on the dissecting table is very obvious. In fact, the size of the two left hands is wider than Lu Chuan's own hand bones.
The growth of bones is related to a certain proportion.
Just like tall people, their shoe sizes will be larger.
In reality, it is rare to see a person who is 1.8 meters tall wearing shoes in the thirties.
Therefore, Lu Chuan first made this judgment.
However, he only said that it was more likely, not absolute.
Because strictly speaking, hand bones cannot be used to identify the gender of a skeleton.
At least, it cannot be used as evidence in forensic analysis.
Because in reality, there are many cases where men and women are of similar height, but their hand bones are about the same size.
There are also many tall women, so hand bones and foot bones cannot be used as forensic standards for determining gender.
"The age...the metacarpal bone is suspected to be female, and the ossification center analysis...should be between thirty and forty years old."
"The bone age of the other two metacarpal bones...is between twenty-five and thirty-five years old."
The age difference given by Lu Chuan was between ten years.
After hearing this, everyone looked at Zhang Yuanchao in unison.
There are not many skeleton cases, and there are not many opportunities for everyone to accumulate experience.
Determine age based on hand bones...
If you can tell the difference between young, middle-aged and old people, you are a master.
As a result, Lu Chuan was able to determine the age range of ten.
real or fake?
As a result, Zhang Yuanchao nodded affirmatively, with a smile on his face called satisfaction.
"Not bad, not bad, you can judge so accurately."
"Leaving aside the judgment of gender, Lu Chuan's judgment of bone age is very accurate. Look here..."
Zhang Yuanchao's level of identification and analysis of skeletons was higher than that of Lu Chuan.
Lu Chuan's skeleton identification and analysis skills were at an intermediate level, while Zhang Yuanchao's skills were at least advanced, or even higher.
"Looking at the development level of the ossification center of the hand bones, we also need to make a comprehensive analysis based on the size of the phalanges. Specifically, I have summarized a set of empirical formulas in this regard..."
Zhang Yuanchao's theory and experience were not included in Lu Chuan's skill card, so he listened very seriously.
Using Zhang Yuanchao's method, the age range of the deceased was narrowed again to the age of five.
The identification and analysis on Lu Chuan's side continued, and the work on site became even busier.
The first bridge pier that was initially confirmed to contain four skeletons has been completely smashed, and the four skeletons have been completely excavated.
The excavation of the second bridge pier is gradually coming to an end.
Finally, all the excavation work was finally completed in the early morning of the next day.
