Wentu/Chen Xinshan (Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology), Huang Ruiting (Fujian Provincial High People's Court), Hu Jiawei (Criminal Investigation Bureau of Wuhan Municipal Public Security Bureau)
In everyday life, everyone hates flies, except forensic experts. Because, in addition to the familiar fingerprints, hairs and blood stains, criminal investigators are now increasingly relying on small insects such as flies to provide clues to the case. Whoever makes them the first to discover and reach the scene of a murder is often them!
Why can flies help solve cases?
The fly's sense of smell is very sensitive, especially for the smell of blood, and it arrives at the scene within 10 minutes of the animal's death. The flies have a high sensitivity to cadaver nitrogen and react at a concentration of 0.04 mg/L, so the flies are known as "the first witness at the scene of death" and "the detective guide of the criminal police".
The olfactory receptors of flies are specially shaped, not only on the antennae around the mouth, but also in large numbers on the feet. Each olfactory receptor is a small cavity that communicates with the outside atmosphere and contains hundreds of nerve cells, so the flies' sense of smell is extremely sensitive, especially fishy odor. When a fly sucks on a fishy smell, it releases a special odor substance that attracts the same kind, causing the flies to flock and gather more and more.
Image source/network
"Sun sickle" cleverly solves strange cases
China's ancient officials mastered the characteristics of flies being bloodthirsty and stenciful, so as to use flies to solve strange cases. Song Ci, the "originator of forensic medicine", recorded a case of drying a sickle in the "Collection of Washed Grievances and Difficult Miscellaneous Sayings":
When an official examined a corpse killed on the side of a large road, he found that the deceased had more than a dozen wounds caused by scythes all over his body, but the deceased's clothes were all there, and there was no property damage, so it was suspected that it was a murder caused by revenge. So he secretly called the wife of the deceased to him and asked, "Who is your husband most enmity?" The wife of the deceased replied, "My husband has never had any grudge against anyone, but recently a man and my husband said that they would kill my husband one day for the sake of debt problems, but they are not people with deep grievances." ”
After inquiring about the man's address, the inspector sent some servants to the vicinity of the house and said, "Each family should hand over all the sickles and let the grand master examine them." Those who dare to hide must be murderers and thieves, and they must be immediately arrested and thoroughly investigated! Soon the inhabitants handed over seventy or eighty scythes. The official ordered the servants to arrange all the scythes on the ground, and it was the height of the summer season, and many flies were gathered on one of the scythes.
The inspector pointed to the scythe and shouted, "Whose scythe is this?" The residents were silent for a moment, and suddenly a man came out and said that it was his, and the inspection officer looked at it, and sure enough, it was the man who had quarreled with the deceased for the sake of debt and declared that he would one day commit murder. The inspection officer ordered the servant to arrest the man and bring him back for interrogation. The man's mouth was still hard, and he cried out incessantly for wrong.
The inspector pointed to the scythe and said, "Take a good look at yourself!" No one else's scythes attract flies, only the murderous blood on your scythe is still there, so that the flies are so concentrated, do you still want to hide? When the people around him heard him say this, they couldn't help but marvel, and the murderer had to lie on the ground and prostrate himself to beg for forgiveness, expressing his willingness to accept his guilt.
This is also the prototype of modern forensic entomology, hundreds of years earlier than the modern entomology that was born in Europe in the middle of the eighteenth century, forensic entomology is still of great significance in the investigation and solving of criminal cases today.