Criminal investigation knowledge

The livor mortis merges into large areas, rigor mortis appears throughout the body, the cornea shows slight turbidity, and the lips begin to shrink. After applying mydriatics and miotics, the pupils still respond. The time elapsed since death is 5 to 6 hours

(2) Displacement: If the body has been moved, the livor mortis will shift. However, if the position of the body is changed 8 to 9 hours after death, only partial movement of the livor mortis will occur, with the old livor mortis still present and new livor mortis appearing simultaneously. After more than 10 hours, the livor mortis will no longer change.

(1) Pressure Marks: Livor mortis is a distinctive mark that appears on the body due to the accumulation of blood beneath the skin as a result of gravitational principles. Between 6 to 12 hours post-mortem, there will be some degree of blanching when pressure is applied; beyond 12 hours, there will be essentially no blanching.

Strangled: There is a distinct deep purple mark on the neck, the pupils are dilated in a state of agony, and the tongue occasionally protrudes and turns a purplish-black color

DNA fingerprinting possesses a high degree of individual specificity, demonstrating consistency across different tissues of the same individual. Its repetition rate is one in several billion, making it virtually unique worldwide.

Traditionally, there are three methods used to infer the time of death: rigor mortis, livor mortis, and body temperature. Detective novelists often utilize these inferences to vividly describe the plot, but one should not take them at face value. This is because the phenomena associated with a corpse are influenced by many factors, such as environmental temperature, the physique of the deceased, level of physical activity, alcohol consumption, and the use of anesthetics.

The face and limbs are cool to the touch, livor mortis and rigor mortis have begun to appear, with a post-mortem interval of 1 to 2 hours

The third aspect is determining the time of death by measuring the temperature of the body. After death, the body ceases to generate heat, and the temperature of the corpse typically decreases by approximately 1 degree Celsius per hour. The temperature of muscle tissue and the surrounding environment significantly affect the temperature of the corpse. The body temperature of obese individuals decreases more slowly than that of lean individuals; the temperature of a corpse in a warm room decreases more slowly than that of a corpse in a cold outdoor environment

In the case of food poisoning, grinding mung beans and mixing them with water for oral administration can temporarily alleviate toxicity

The surface of a pearl is composed of calcium carbonate, which is particularly vulnerable to acidic corrosion. Therefore, when handling precious pearls, it is essential to wear gloves or wrap them in a handkerchief. Failing to do so may cause the pearl to come into contact with the oils on one's hands, leading to a more rapid loss of luster on the pearl's surface. The luster of a pearl's surface lasts a maximum of 30 to 40 years, after which it will gradually fade.

Generally, individuals who have been missing for more than seven years are confirmed deceased. In cases of disappearance due to natural disasters or calamities, a person is declared dead after one year of being missing

Using tea to cleanse the wound and neutralize toxins is the best method for treating bites from sea snakes and similar creatures, as the tannins present in tea can detoxify; additionally, the person responsible for sucking out the venom should also rinse their mouth with tea to prevent poisoning

Burying the body in the ground, preventing it from coming into contact with air, will result in the decomposition rate being 1/8 of the normal speed, while in water it will be 1/2 of the normal speed

Carbon Dioxide Poisoning: If the concentration of carbon dioxide in the surrounding air exceeds 20%, inhalation can lead to severe convulsions, resulting in death from biting the tongue within a few seconds, accompanied by a cold body. Carbon dioxide is heavier than air, thus it settles at the bottom of confined spaces

If a deceased person is strangled and then struck on the head with a blunt object, it can result in severe intracranial injuries and death due to respiratory system failure

Poisoning: The lips first exhibit a slight purplish or black discoloration, followed by similar phenomena in other parts of the body; the eyes may sometimes bulge, the hands may clench into fists, and the waist and legs may curl up.

In actual forensic work, the time of death for most deceased individuals can be easily determined through their family members and informed witnesses, without the need for specialized inference. However, in cases involving unidentified corpses, floating bodies in rivers, dismembered bodies from homicides, relocated bodies, and other instances where the time of death is unclear, accurately inferring the time of death can often provide a scientific basis for analyzing the time of the crime and determining the scope of the investigation

Consuming a certain amount of sodium nitrite can also lead to death. Acute poisoning occurs with only a small amount of toxicity entering the bone marrow

How criminals can use temperature, humidity, and other methods to confuse forensic judgments. For instance, the recent puzzle involving the subtle thermometer is a simple application of this knowledge. Understanding this relevant information not only helps in responding to related content but also aids in attempting related creations. Therefore, I am sharing this excerpt with friends who may be interested.

Striking a person's head with a blunt object can even cause lacerations. Typically, the first blow does not result in blood splattering, but there will be bruising around the wound. It is only after a second strike to the same area that blood will spurt out

Rigor mortis typically begins to appear 1 to 3 hours after death, initially manifesting in the facial area and ocular muscles, and subsequently spreading to the upper and lower limbs of the trunk. After 12 hours, rigor mortis reaches the entire body. It lasts for approximately 18 hours before starting to alleviate, at which point the body begins to soften.

2. Observe the changes in livor mortis

3. Determination of death through autopsy.

The burns caused by the current flowing from the fingertips into the body will turn the fingers grayish-white

The mucous membranes of the upper and lower lips exhibit bleeding, there are pinpoint epidermal erosions on the neck, and there are patchy hemorrhages on the skin, along with conjunctival hemorrhage, indicating a process of strangulation

3. The digestive contents within the corpse indicate that food takes approximately 2 hours to be fully digested in the stomach before reaching the small intestine

Drowning: Slight water stains in the air, dilated pupils, and bleeding phenomena on the eye mucosa. The eardrum may also rupture due to water pressure, causing bleeding

4. Observe the degree of decomposition of the corpse

Suicide, when a gun is pressed against the head, will leave scorched marks around the bullet hole, and the surrounding skin will also darken in color. Additionally, the entry wound of the bullet is smaller than the exit wound, and there is generally less blood flow. Typically, scorched marks are only left in cases of suicide.

1. Observing the degree of rigor mortis, under normal circumstances, a body will begin to stiffen within 30 minutes to 2 hours after death, becoming completely rigid within 9 to 12 hours, softening after 30 hours, and returning to its original state after 70 hours. However, if the body is in soil or water, or in low-temperature dry conditions, this process will be delayed, while high-temperature and humid conditions will accelerate it

The deceased's hair was slightly singed, and the muscles of the body were extremely rigid, which are characteristics of death by electrocution under high voltage

Pulmonary perforation, even if one wishes to breathe, will result in an inability to expand the lungs, leading to difficulty in breathing. This can cause asphyxiation and death. Before death, one may struggle in pain for approximately 10 to 15 minutes

In both domestic and international forensic research, the forensic determination of time of death has always been an extremely important topic. The research methods have gradually evolved from visual observation to advanced technical examinations such as histology, histochemistry, biochemistry, and biophysics. However, due to the changes in the corpse being influenced by various internal and external factors, it is impossible to establish a completely uniform standard. The use of various methods to infer time can only provide an approximate time, not an absolute precision. Nevertheless, due to the changes in the corpse being influenced by various internal and external factors, it is impossible to establish a completely uniform standard. The use of various methods to infer time can only provide an approximate time, not an absolute precision.

Typically, rigor mortis begins to set in within 30 minutes to 2 hours after death, with full body rigidity occurring between 9 to 12 hours later. This state of rigidity lasts for approximately 30 hours, after which the body begins to soften, returning to its original state after about 70 hours. This is generally the case; however, if the surrounding temperature exceeds 35 degrees Celsius, both the onset of rigor mortis and the subsequent softening will accelerate, with recovery occurring in as little as 24 hours. Following intense physical activity prior to death, proteins in the body are more prone to coagulation, resulting in a faster onset of rigor mortis than usual. This is generally the case; however, if the surrounding temperature exceeds 35 degrees Celsius, both the onset of rigor mortis and the subsequent softening will accelerate, with recovery occurring in as little as 24 hours. Following intense physical activity prior to death, proteins in the body are more prone to coagulation, resulting in a faster onset of rigor mortis than usual.

The appearance of livor mortis follows a certain temporal pattern. After death, blood circulation ceases, and within as little as 30 minutes, blood accumulates in the lower vessels of the body due to its own gravity, resulting in purplish-red marks on the skin, resembling red wine at the bottom of a bottle; this is known as livor mortis. Livor mortis appears no later than 4 to 10 hours after death. Its coloration persists for a long time. If a person lies on their back after death, livor mortis should be present on their back; if livor mortis is found on the front of the body, it indicates that the corpse has been moved. Livor mortis appears no later than 4 to 10 hours after death. Its coloration persists for a long time. If a person lies on their back after death, livor mortis should be present on their back; if livor mortis is found on the front of the body, it indicates that the corpse has been moved.

If the echo in the cave is loud, it indicates that there is no way out; if the echo is faint, it suggests that there is still a path.

In detective novels, the inference of the time of death often holds significant importance. Generally speaking, the earlier the body is discovered, the more accurate the time of death can be inferred. It is common to see that once the forensic expert determines the time of death, the first thing the officer does is to question the suspects about their whereabouts at the time of the incident, that is, to establish an alibi. A considerable number of works also revolve around this.

(3) Note: It is important to consider the age, physique, cause of death, and environmental factors surrounding the placement of the body, as different factors can lead to significant variations

If poison is applied to the flower, the flower itself should first wither

The skin of the deceased appears pink, with some spots protruding from within the skin, clearly indicating death due to sodium hydroxide (NaOH) poisoning; if the poison is in a capsule, it would take at least 15 minutes to dissolve and exhibit toxicity. During first aid, it is advisable to rinse the mouth with a protein-containing substance, such as milk. PS: Potassium cyanide is poorly soluble in cold water

The following formula is commonly used to infer the time of death

Mixing hydrochloric acid with acidic cleaners will produce toxic gases

If a person's internal organs are ruptured, there will be a distinct visceral odor

There are many types of toxic fungi, some of which can emit highly poisonous toxins. Toxic fungi can also be used to make medicine, but they still possess toxicity, so it is best not to consume them regularly

( Room temperature (98.6°F) - rectal temperature of the corpse ) / 1.5 = approximate time since death

The livor mortis presents a patchy distribution, with rigor mortis mostly appearing, indicating a time of death of approximately 3 to 4 hours ago

A deep and noticeable mark is often left on the index finger of a surgeon, which is a result of frequently tying sutures

Sodium thiosulfate (bleaching agent) can neutralize potassium cyanide toxicity. (Here, I would like to thank the author of "Angel Boy Detective," Kazekaze Hitori)

On the surface, it appears to be a death caused by biting the tongue, referred to as "suicide"; at times, this may be due to inhalation of toxic gas or the ingestion of poison leading to spasms.

If spasms are caused by significant bleeding, it is essential to tightly bind the area around the wound with a rope to prevent excessive blood loss. The next step is to massage the heart.

Consumption of potassium cyanide may lead to asphyxiation and death (potassium cyanide has an almond-like odor)

II. The Remarkable Inference of Time of Death

I. Knowledge of Autopsy