Qin Hui, Wu Qiming, Wang Ruiqing and other people from the QZ City Criminal Investigation Detachment did not sleep all night.
At the edge of the ruins of the Minghe Bridge, Li Donglin supervised the battle all night.
Leaders from the provincial department supervised the operation, and all resources were sent to the scene as soon as possible.
The emergency lighting vehicle illuminated the entire scene as if it were daytime.
More than 30 fire emergency personnel took turns working, using small hand-held blasting hammers to hammer the cement of the bridge pier bit by bit. After nearly 20 hours, at dawn the next day, all the bones were finally cleared out.
However, no one was excited about completing the work. Instead, everyone's heart sank to the bottom.
Four skeletons were unearthed from the first bridge pier.
In the second pier, three skeletons were unearthed.
A bridge over 100 meters long with thirteen piers, seven skeletons were unearthed!
The air in early spring is still cold, and the chill blows into everyone's heart.
"Seal the scene and return the bones to the detachment."
QZ City Criminal Investigation Detachment, Forensic Laboratory.
Lu Chuan and others slept for a while last night and are now in good spirits.
However, facing the seven skeletons, his expression was also very ugly.
Let’s not talk about who these people are and how they died, let’s just talk about seven people!
There was no news at all back then!
How can it be?
The complete skeleton was excavated, and the most important thing was to confirm the identity of the skeleton.
The first is to determine the cause of death of the deceased.
"Skeleton No. 1, the fourth rib of the left rib was scratched with a sharp object. The preliminary cause of death is that the sharp weapon pierced the heart..."
"No cement residue was found in the brain cavity of Skeleton No. 1. It was poured into the cement pier after death."
"Skeleton No. 2 has a comminuted fracture of the right leg bone, a dislocated fracture of the left arm, fractures of the third and fourth ribs of the left rib, and signs of bone cracks in the seventh rib of the right rib."
"Broken hyoid bone, death from suffocation..."
"Skeleton No. 3 has a skull fracture, a broken neck, a fractured sixth rib on the left rib, and a dislocated fracture of the tibia of the left leg."
"Skeleton No. 4 has percussive bone fracture scars on the right arm..."
The students who can follow Zhang Yuanchao are called students, but their actual forensic skills are higher than those of many grassroots units.
There is knowledge in theory about the more complex identification and analysis of skeletons, but the practical experience is lacking.
But these people have no problem doing ordinary skeletal injury assessment.
Each skeleton has injuries, and most of these injuries can directly determine the cause of death.
For example, if the hyoid bone is broken, under normal circumstances, the hyoid bone will form a separate entity after the corpse becomes white and ossified.
Without being damaged by external force, there is a high probability that it will not break.
Therefore, generally speaking, as long as the hyoid bone is found to be broken in the skeleton, it can basically be determined as death by asphyxiation.
Other corpses basically had obvious skeletal injuries.
Among the seven corpses, it can be clearly judged from the injuries on the skeletons that they all experienced varying degrees of abuse during their lifetimes.
This basically rules out the possibility of accidental death and hiding the body.
In addition, three of the seven people were poured into the bridge piers while they were still alive.
The other four people were poured into the bridge pier after losing vital signs.
The most important task of forensic medicine and current investigation is to determine the identity of the victim through technical means.
The cause of death has basically been confirmed. The DNA extraction of the skeletons was done by Zhang Yuanchao's students. Lu Chuan was responsible for determining the specific time of death of the seven people.
The skeletonization time of corpses varies greatly under different external environments.
In a natural environment with high temperature and high humidity, without external factors such as bites from wild beasts, bones will turn into white bones in as little as half a month.
For example, in tropical rainforests, after a human body dies, it begins to decay a day later before rigor mortis has completely disappeared.
defeat.
After three days, the complete giant phenomenon will be formed.
After a week, the muscles will rot and melt away, leaving only the skin covering the surface of the corpse.
In ten to fifteen days, the parasitic flies inside the corpse will digest it completely, leaving only gray and black bones.
During the weathering process, the gray-black bones will gradually turn into snow-white.
Generally speaking, the whiter the color of human bones, the longer it took to die.
However, it is impossible to accurately know the time of bone formation by relying on color alone.
Lu Chuan still has to do some experiments.
The concrete used to build bridge piers is different from ordinary concrete.
There are many kinds of concrete grades, and the application occasions are different according to the nature of the project.
Cement grade is the strength index of cement, which measures the solidity of cement after mixing, setting and hardening.
There are many factors that affect the strength of cement, such as the mineral composition in the cement, particle size, temperature and humidity during hardening, etc.
The cement used for the piers of the Minghe Bridge is low-temperature Portland cement, which has better water resistance than ordinary Portland cement.
The body was sealed in the cement can during the process.
After fifteen years, the corpses inside have been transformed into bones, but the specific time of death is still difficult to determine, especially the four corpses that were already dead when sealed.
The experiment was very simple. Lu Chuan wrapped a chicken leg with cotton cloth and used the same cement as that year to seal it.
Then by adding some chemicals, changes over fifteen years are simulated.
This all depends on experience. There are opinions on what substances to add and how much to simulate the time changes of fifteen years.
While the current investigation side is busy, the front-line criminal police of the QZ City Criminal Investigation Detachment are also not idle.
The winning bidder for the construction of the Minghe Bridge that year was the QZ First Bridge Construction Group Company, and the project construction unit was its subordinate Highway and Bridge Construction Branch.
The Minghe Bridge was a key project in QZ City at that time, and the relevant project information is very complete.
Fifteen years is not a short time, but it is not that things have changed.
Those who were in charge of the project were arrested one by one.
The workers who were responsible for pouring concrete back then are also searching, and the search is focused.
After the concrete pouring is completed, it still needs to be vibrated, especially the vibration of the bridge piers, which is extremely demanding and must not have any construction defects.
After the maintenance is completed, professional quality inspection is required.
So, how did the bridge pier pass the inspection when corpses were poured into it?
Is the worker responsible for vibrating one of the murderers?
The reason why I say one is because seven people died, and the watering of the bridge piers could not be interrupted.
In other words, the four corpses and the three corpses in the two bridge piers where the corpses were found were at least watered separately and at the same time.
That cannot be done by one person.
Because the project is ongoing, it requires the coordination of multiple types of work.
The arrest and interrogation work were carried out simultaneously.
