Attending ex-girlfriend's wedding, arresting the groom's officer on the spot

The body was transported back to the Criminal Investigation Detachment in the afternoon.

Zhang Kai was wearing a protective mask, and his rubber gloves made a ringing sound when they collided with metal instruments.

The cold air in the autopsy room was filled with a foul smell. Assistant Xiao Wu endured the discomfort and pointed the camera at the autopsy table.

Zhang Kai wore three layers of latex gloves and tapped the female corpse's knees with his knuckles, making a dull sound. The originally stiff joints slightly rebounded, and under the bluish-gray skin, the cord-like muscle lumps formed by rigor mortis were gradually softening.

"Xiao Wu, write down the time." Zhang Kai pulled out the metal thermometer inserted into the rectum of the corpse. The LCD screen glowed with blue numbers. "22 degrees." He pulled the notebook on the dissection table and circled the time of the crime on the temperature curve with a red pen. "The lowest temperature in the past few days was 5 degrees at night, and it rose to 15 degrees during the day, which is in line with the rule that the body temperature drops by 0.5 to 1 degree every hour."

Assistant Xiao Wu stared at the densely packed formulas in the notebook, his pen tip suspended in the air: "Forensic Doctor Zhang, can the time of death be determined based on the body temperature alone?"

"Of course not." Zhang Kai dipped the thermometer into the disinfectant, and the metal collision sounded crisp and harsh. "The body temperature is greatly affected by the environment. Look--" He opened the corpse's eyelids, and the translucent cornea was covered with a light white fog. "Corneal opacity level II, indicating that the death has exceeded 72 hours. Combined with the degree of rigor mortis relief," he held the corpse's wrist and gently turned it. The joints that were originally as stiff as steel bars began to loosen slightly. "The large joints began to soften, which is the characteristic of 72 to 84 hours after death."

Xiao Wu suddenly realized: "So we need to make a comprehensive judgment from many aspects?"

"That's right." Zhang Kai put on goggles. The moment the scalpel cut open the chest and abdominal cavity, a strong stench hit him in the face. "The degree of digestion of food residues in the gastrointestinal tract, the fixed position of corpse spots, and the activity patterns of insects." He picked up a section of small intestine with tweezers. The dark red mush inside still contained undigested food particles. "The contents of the deceased's stomach were semi-fluid, and the food in the intestines was pushed to the end of the ileum, indicating that he was killed about 3 hours after the meal. Only by putting these clues together can we draw an accurate conclusion."

Xiao Wu hurriedly took notes and suddenly remembered something: "Then is the judgment method the same in summer and winter?"

"The principle is the same, but the parameters need to be adjusted." Zhang Kai pointed to the thermostat on the wall, which stored the temperature change data of the corpse in different seasons. "In a high temperature environment, the corpse decays faster and the temperature drops slower; in a low temperature environment, the decay is delayed, but the cooling process is accelerated. Just like the case in Beishan Park this time, the low temperature at night delayed the decay of the corpse, but made the temperature drop faster."

The scalpel precisely cut open the skull of the deceased. Zhang Kai's voice mixed with the hum of the craniotomy saw: "Remember, no single indicator can completely determine the time of death. Rigor mortis may occur earlier due to strenuous exercise, livor mortis may change position due to the body position, and even the abnormal body temperature of the deceased before death will affect the judgment." He held up the separated brain, and the pale tissue was stained with a corrupt blue-gray color. "What we have to do is to piece together the truth of time from every detail of the body like a detective."

The sour stench became stronger after the chest and abdominal cavity were opened. Xiao Wu's Adam's apple rolled violently, and the camera lens shook with it. "Hold it." Zhang Kai didn't even raise his head, and clamped the trachea accurately with tweezers. "The respiratory tract is clean, and he didn't die of suffocation. Look here--" He turned the body over, and the sunken wound on the back of the neck was a strange purple-blue. "First knock him unconscious with a blunt object, and then strangle him. It's a typical double-killing method." "Can you identify the murder weapon?" Xiao Wu's voice was tense. Zhang Kai held up the fiber picked out from the subcutaneous tissue: "Cotton rope, with a rough surface, it may be a household item like a clothesline." He suddenly moved close to the neck of the deceased, and the fine dandruff on the edge of the strangulation mark was clearly visible under the magnifying glass. "Send it for examination together with the skin tissue between the fingernails. I hope the corruption doesn't damage the DNA."

The autopsy light was sizzling overhead. When Zhang Kai cut open the stomach, a rotten pulp mixed with the smell of seafood gushed out. "Vomito?" Xiao Wu stepped back subconsciously. "What he ate before he died." Zhang Kai scooped up the brown paste with a spoon, "Shrimp shells, crab meat, and red wine residue. The degree of digestion shows that he was killed two to three hours after the meal." He divided the sample into three portions, and the metal tray made a crisp sound. "Check the takeout records of mid- to high-end restaurants in the city, and focus on the seafood set meal."

Next is the analysis and judgment of the deceased's age.

Zhang Kai placed the scalpel on the tray, and the sound of metal collision was crisp and sharp. "Xiao Wu, prepare to measure the pubic symphysis." He took off his blood-stained gloves, put on a new pair of gloves, and stared at the pelvic area of ​​the female corpse.

Xiao Wu quickly handed over the vernier caliper and magnifying glass, and asked doubtfully: "Forensic Doctor Zhang, can the age of the deceased be determined by the pubic symphysis? What is the principle behind this?"

Zhang Kai took the tool and used tweezers to carefully push aside the obstructing tissue, revealing the rough bone structure of the pubic symphysis. He said, "The morphological changes of the pubic symphysis will show regular changes with age, which is an important basis for judging age. When you are young, the pubic symphysis is relatively flat, with obvious ridges and grooves. As you age, the ridges will gradually disappear, the surface will become smooth, and bone hyperplasia will slowly form on the edges."

He pointed the magnifying glass at the pubic symphysis and motioned Xiao Wu to take a closer look. "Look, although the pubic symphysis of the deceased has been worn to a certain extent, the ridge is still faintly visible. The groove in the middle of the symphysis is beginning to become shallower, and there is slight bone hyperplasia on the edge. According to the standard atlas of Forensic Anthropology, this feature is consistent with the change pattern of the 25 to 30-year-old age group."

While taking photos, Xiao Wu asked, "Do you only rely on this one spot to make your judgment? Will there be any errors?"

"Of course not only that." Zhang Kai straightened up and rubbed his sore shoulders. "We also have to combine the wear of the teeth and the degree of closure of the skull sutures to make a comprehensive judgment. Take the teeth for example," he gently pried open the deceased's mouth with pliers, "the occlusal surface of the deceased's molars has moderate wear, and the enamel has been consumed to a certain extent, but the pulp cavity has not been exposed, which also points to the age range of 25 to 30 years old."

As he spoke, Zhang Kai picked up the electric saw and prepared to open the skull: "The closure time of the skull sutures varies greatly from person to person, but it can also be used as a reference. When we open the skull later, we will observe the closure of the coronal suture and sagittal suture, and then verify it with the judgment results of the pubic symphysis and teeth, and we can reduce the error to the minimum range."

The buzzing sound of the electric saw sounded, and white bone chips flew. After a moment, the skull was carefully opened. Zhang Kai pointed to the gap inside the skull with tweezers: "Look, the front half of the sagittal suture has begun to close, but the back half is still clearly visible, and the coronal suture is also partially closed. These are consistent with the age characteristics reflected by the pubic symphysis and teeth. So based on a comprehensive judgment, the deceased is about 28 years old, with an error of no more than two years." (End of this chapter)