C36

For this trial, Shen Yuan prepared a series of slides, including the anatomical drawings taken at that time, the videos of his field simulations, as well as the diagrams drawn from the data he recorded during his experiments, and the appropriate written instructions.

"For all forms of flora and fauna, a corpse is an island that has just revealed the surface of the sea, with all kinds of extremely rich resources on it. From the start of decay to the end of resources, the greatest contribution is made by scavengers. And most of the scavengers are arthropods, what we call insects. Under natural conditions, the corpse was quickly covered with a variety of biological species. During different periods of decay, different species of organisms would appear. As for the same kind of creatures, after occupying a corpse, they would appear again in cycles or have a regular life time. This provides a basis for our entomology to solve cases.

Flies reach the body first and lay large numbers of eggs in the natural orifices or deep wounds. The life cycle is usually divided into four stages: eggs, larvae, pupae, flies and adults. Considering the fact that the time of the victim's death differed very little from the time of the autopsy, I shall focus here only on the eggs and larvae of the flies. The main reason for this is to give a scientific and objective account of the reasons behind my subsequent defence of the case. "

Shen Yuan continued, "After a fly lays an egg, the time at which the egg hatches varies, depending on the local temperature and the type of fly that appears. In the early spring season, according to the data, the carcass eating flies in the south of Hunan are mainly Giant Tail Aria. Later, when I was experimenting with dead pigs in the field on Bird Island, I caught the adult and compared it with the adult that Sheriff Leigh had taken from the victim. The biological characteristics of the two were consistent, objectively confirming the data. Therefore, the main experimental data needed to estimate the time of death of the victim are based on the activity patterns of eggs and larvae formed by the giant tailed alligator on the carcass.

As for the temperature, I checked the weather records of the city of Lai last year. The temperature data of three days are as follows: 20 ℃ ~ 14 ℃, 21 ℃ ~ 15 ℃, 23 ℃ ~ 16 ℃, average temperature 18 ℃.

After hatching, the larvae feed on the dead, so the time of death can be determined according to the growth and development of the larvae. One of the important indexes of larval development is body length.

At 18 ℃, it took 1.35 days, or 32.4 hours, for the giant tail to lay its eggs. It takes 158 hours to develop a larva of 17.09 mm, and the time it takes to develop a larva of 1 mm is approximately 9.24 hours. In other words, after laying eggs, the giant tail Arias developed into a 1 mm larva, which lasted for 32.4 hours plus 9.24 hours, or 41.64 hours. When the victim's body was dissected, the maximum length of the larva was close to one millimeter. What sort of concept was this? In other words, the victim had been killed more than forty-one hours before the autopsy. Assuming that the accused committed the murder at one o'clock in the afternoon of the day before the autopsy, the difference between the time of the crime and the time of the autopsy is only 28 hours. So, here's the question. Where are the 13 hours to go from the time of death provided by entomological evidence? Therefore, it can only be assumed that the victim's death occurred during the period prior to the defendant's entry into Bird Island. "

The court was in an uproar.

"Wait." The prosecutor said, "Excuse me, great Mr. Entomologist. According to your conjecture, the time of death should have occurred late at night, around midnight, before the defendant left for Bird Island. However, flies do not come out at night, and the temperature at night is also low, not conducive to flies spawning. And how do you explain that? "

"The question posed by Mr. Prosecutor is precisely what I am going to say next that requires further explanation. The above figures are based on a temperature of 18 degrees. The eggs and larvae of Aria gigantica stop growing at less than eight degrees, so the time of spawning and larval development of Aria gigantica is continuous under the current climatic conditions. "

Shen Yuan drank a mouthful of water and continued saying, "In entomology, zombie-eating flies have to satisfy a certain amount of heat requirements in order to complete a certain period of development. This is called effective accumulated heat. At 18 degrees Celsius, it took 41.64 hours for the giant tail of Aria gigantocephalus to develop from eggs to 1 mm larvae, and the total effective accumulated temperature was calculated to be 41.64 hours by 18 degrees, that is, 749.52 hours. When the feeding environment of giant tail Arias is not 18 degrees but 28 degrees, the time for larvae to develop into one millimeter will be shortened because the total effective cumulative temperature is constant. The calculated time is 749.52 hours divided by 28 degrees, that is, 26.77 hours, which is, the time is greatly shortened. This means that after one o'clock, the defendant can kill the victim in accordance with the laws of entomology. However, all three of his friends had testified to having seen the victim on Bird Island. Yang Wen stayed with them until five o'clock when they left Bird Island. Besides, Yangwen would have to spend some time hiding the body in the cave.

Forty-one hours is a number calculated on the assumption that 18 degrees are constant, while 26.77 hours is a number calculated on the assumption that 28 degrees are constant, which is two extremes. None of it fit the facts of the case. To reflect more objectively the facts of the case, we might assume that the body was moved from a temperature of 28 degrees to the ship in the evening, exactly 24 hours after the autopsy. In other words, the body spent 24 hours in an environment of 18 degrees Celsius. The effective cumulative temperature for this period is 24 hours by 18 degrees, that is 432 hours. The effective cumulative temperature obtained from the reduction of the total effective accumulated temperature by 749.52 hours to 432 hours is 317.52 hours, which is the effective accumulated temperature of the corpse under the temperature of 28 degrees Celsius. Dividing 317.52 hours by 28 degrees, it is not difficult to conclude that the body was placed in an environment of 28 degrees for 11.4 hours. The total time to die was 35.4 hours from the time of the autopsy, which meant that the body was still dead at around 6 a.m. on the 26th. "

"Excuse me, what was the reason for your mention of the corpse cave?" the prosecutor asked.

"To answer that question, you have to mention the simulation field experiment I did on Bird Island three months ago." Saying that, Shen Yuan used the projector to release the video footage of his experiment on Bird Island, "I will place the corpses of three pigs in three different locations. One was placed in the dry part of Bird Island, one in the boat, and one in a secluded cave at the foot of the Goose-Ridge on the opposite side of Bird Island, probably unknown to the rest of the world.

There were two well-known places near the Gosling Mountains. One of them was a chemical factory that specialized in producing barite. The main ingredient of barite was barium sulfate. The other is the famous Sulfate Hot Spring scenic spot. This indicates that the geological structure of the Gosling Mountain is different from that of other places, and is rich in sulfur and geothermal. This cave was located right above the geothermal environment, and it was equivalent to an air-conditioned room. The temperature inside would not change throughout the year. The climate of the cave, like that of a tropical island, could not be compared with that of the surrounding area. My data showed that the temperature was around 29 degrees and the humidity about 73%, which is a good environment for rapid development of flies. I suspect that the victim was killed in a cave and then transferred to Bird Island, where he was thrown into a boat and blamed on the defendant. "

"I think he's talking nonsense." The prosecutor couldn't help pointing angrily at Shen Yuan, "This kind of assumption is just a random guess. It can only appear in the plot of a science fiction novel, and can't be explained scientifically."

Shen Yuan slightly smiled, "Regarding this, I have specially compared and analyzed the sulfur content of the larvae on the corpses in the cave and on the island. The results showed that the sulfur content of the larvae on the corpse of the bird island was 0.18% and that on the corpse of the cave was 0.31%, there was a significant difference between the two. In view of this, I have commissioned a sample analysis of the larvae in the bodies of the victims from the police medical examiner in Lai City. "

"Please send the medical examiner onstage." The presiding judge said.