Bodies were hidden on the walls of the rental house, severed limbs were found in cement piers, and skulls were dug up at the construction site...... In every city with many high-rise buildings, there is an urban legend of "cement sealing corpses".
On May 8, a "cement body sealing case" in Fuyang City, Anhui Province was announced to be solved. This unique modus operandi has also been brought from legend to reality with a police report[1].
However, how did the corpse that was firmly sealed in the cement pier see the light of day and be wronged?
As one of the most important building materials, cement is everywhere on the construction site or for home decoration. Buying cement at the building materials market rarely arouses suspicion from the neighborhood, and after about six hours of hydration and hardening, the cement condenses into a hard stone [2], making it easy to "hide" the contents of the package.
If a certain amount of sand and gravel is added to the cement, concrete with greater compressive resistance can be prepared [2]. The stone body formed after concrete solidification and hardening is harder and less likely to be damaged or eroded.
Cement is a common binder in building materials and is widely used around the world
The murderer fantasized that by sealing the body in cement, he would be able to merge with various buildings and complete a textbook "perfect crime". This wishful thinking is a little abacus, and even the king of Yama can hear it clearly.
However, the corpses sealed in cement are trying to use their own ways to continue to send "distress signals" to the outside world.
Spoilage bacteria generally begin to multiply in the intestinal lumen 3 to 6 hours after death [3]. However, cement and concrete, with lime as the main component, not only provide highly alkaline conditions, but also isolate the corpses from the outside world [4][5]. Such an environment with poor air circulation and low oxygen content weakens the rate of growth and reproduction of spoilage bacteria [3][6].
The gnawing of carcasses by carnivorous and rodents also accelerates the natural process of decay of carcasses [7]. The confined environment created by cement and concrete protects the carcass from animal predators [5].
[8] With the double overlap buff, the decay process of corpses is significantly slower.
Under the action of insects such as maggots, flies, and various microorganisms, the corpse takes on different forms and characteristics at various stages of decay / Unsplash
Under normal circumstances, 24 to 48 hours after death, the corpse begins to decompose, and the notorious "giant view" will be formed in 5~7 days, while the time for the body of the adult corpse to ossify on the ground only takes more than 6 months [9]. However, the body of a woman, wrapped in plastic film and embedded in concrete, was found 5 years and 10 months later in a well-preserved state [10].
In addition, studies on the chemical decomposition of cadaverics have shown that decay is associated with a variety of volatile organic compounds and that the odor emitted by corpses can change over time [11].
In other words, sealing the corpse in cement or concrete not only does not prevent the formation and spread of the corpse odor [4], but also stretches the production line of the foul odor gas longer because it delays the decay.
The seemingly airtight cement block actually has many tiny cracks on the inside [12]. Although some cracks are only 0.05 mm wide, they are large enough for odors to seep out [13][14].
The quality of cement and concrete depends on the ratio of raw materials, and it is often difficult for ordinary people to ensure the same high standards as the construction site
What's more, the existence of the corpse also buried the hidden danger of cracking the cement block, and the smell of the corpse had nowhere to hide.
Under normal circumstances, the crushed stone in the concrete will gradually sink under the influence of its own weight, eventually making the mud block "shorter" [15]. The settlement of each part of the evenly mixed concrete is similar, and the interior is less likely to "pull on each other", resulting in uneven tension.
But the case of the corpse is a different story.
Some of the rubble stopped sinking after hitting the corpse, and the particles next to the corpse still had a long way to go, and there was still a lot of room for sinking. When the amount of settlement of each part is too different, the resulting shrinkage force will cause the cement block to crack once it exceeds the tensile limit of the concrete [15].
Through these cracks, the stench of corpses drilled out of the surface, into the walls, and into the nostrils of every passerby. Although it will not be stinking for 10,000 years, it is more than enough for a few weeks or months, which is enough to make people around them can't help but suspect that "there are ears on the wall", "there are people under the bed", and there are undead spirits on the soles of their feet.
In addition, changes in environmental factors such as temperature, humidity, and air corrosiveness may make these gaps larger and larger. In this way, it is not uncommon for half a skull or a foot to "jump" out of a cement bucket on a hot summer day, or under the erosion of the sea breeze [12].
The gradually cracking cement blocks provide important clues for the earlier discovery of the corpse / Picture worm idea
However, compared with the cement blocks that have been condensed into hard lumps, it may be the murderer himself who is easier to "break the defense".
In most cement sealing cases abroad, the murderer will seal the body nearby, either in his cellar and attic, or in the garden and court outside the house [16]. The victim is also usually a close woman or child who lives with the killer [5]. You can't miss it every day, and after a long time, there will always be a day when you can't hold on to the fear or guilt in your heart.
Moreover, when the police investigate and investigate the connections of the missing people, they will visit their relatives and friends as soon as possible. After several suspicions and inquiries, it is not surprising that the disappearance turned into a homicide. According to a report from a foreign study of cement-sealed corpses, in 5 of the 6 rare cases, the suspects confessed to the crime [16].
Even if the murderer has a strong heart, the body is hidden deeply, and it does not see the light of day for many years, which does not mean that he has escaped prison. There will still be construction teams and repair teams to patronize your crime scene and let the truth see the light of day.
Forensic science research has reported a case of cement sealing of corpses spanning 20 years, in which the skulls chiseled out by the demolition team with a piling machine allowed two unjust souls from 1998 to be blinded [8].
After the body is sealed in cement, the characteristics and injuries from the past are likely to be preserved, providing a favorable clue for criminal investigators to find the source of the body and identify the cause of death / Unsplash
Once the body sealed in cement is found, the time is not far before the murderer will go to prison.
Although cement delays the decomposition of corpses and affects the forensic doctor's judgment of the time of death [4], it is also because of this that the crime scene and the identity of the deceased can be preserved.
The corpse wax formed in the alkaline environment of cement pouring can retain traces of premortem injuries such as strangulation marks and fractures, and help forensic doctors confirm the true cause of death of the deceased [17][18]; The police were also able to use the method of pouring molds to make silicone molds of the deceased's face or hands from the cement blocks that originally covered the deceased, so as to identify them [5].
Cement may be able to seal the heart, but it can never seal the brutality and reality of the murderer's killing.