lcionline Chapter 1117 Autopsy
Chapter 1117 Autopsy
"Could the woman in red seen by the landlord be an accomplice of the unknown man?" He proposed a hypothesis: "The two worked together, one acting as lookout while the other committed the crime, and then moved the low cabinet to dispose of the murder weapon or the body?" However, this speculation lacked empirical evidence. The fingerprints and footprints only pointed to a single man, and the woman in red's traces were only a few fibers, making it impossible to confirm her identity.
In the investigation van late at night, Xiao Yang and Xiao Sun stared at the table piled high with evidence bags, their faces clouded with worry. Fingerprints, footprints, fibers, bloodstains, blind spots in the surveillance cameras… every clue seemed important, yet none could form a coherent conclusion. “The traces we found after expanding the search area have only made the case more complicated,” Xiao Yang said, rubbing his sore eyes. “What was the motive of that unknown man? A debt dispute? A crime of passion? Or was he a hired killer?” Suddenly, a message popped up on Xiao Sun’s computer: the deceased Zhang Lei’s bank statements showed a remittance of 50,000 yuan on July 2nd to an unknown account with vague account holder information.
“This could be the breakthrough,” Xiao Yang immediately retrieved the account’s transaction records, “but the bank is located outside the province, requiring cooperation in the investigation, and it will take at least three days to get results.” The neighborhood outside the window gradually fell silent, only the hazard lights of the investigation vehicle still flashing, illuminating the two men’s tired but focused faces. They knew that these seemingly scattered clues must contain the key to the truth, but now, they needed more patience and technology to bring them to the surface.
While Xiao Yang and Xiao Sun were conducting a more detailed examination of the scene, the body had already been transported back to the Criminal Investigation Detachment for autopsy.
The stainless steel table in the autopsy room gleamed coldly under the operating lights. When Zhang Lei's body was brought in, fibers from the living room carpet still clung to its surface. Zhang Lin, wearing double-layered rubber gloves, released a strange odor—a mixture of putrid gas and the chill of the air conditioning—the moment his fingertips gripped the zipper of the body bag. "First, perform a 3D scan of the body surface," he told his assistant, Xiao Lin, without looking up. The scanner's laser beam moved across the body's surface. "Pay close attention to the distribution of abrasions and contusions on the back, especially the linear wounds below the shoulder blades, and compare them with the drag marks found at the scene."
Xiaolin adjusted the scanner's parameters, and the point cloud model on the screen gradually outlined the corpse's contours. "Teacher Zhang, there's a 5x6cm subcutaneous hematoma on the right temporal region of the deceased," she said, placing a ruler at the edge of the hematoma. "The wound edges are irregular, with epidermal abrasion, which looks like it was caused by a blunt force trauma." Zhang Lin leaned closer to examine it, gently pressing his fingers around the hematoma; the decaying skin trembled slightly under his fingers. "The width of the contusion is 3.2cm, consistent with the contact surface characteristics of a flat blunt force, possibly a wrench or a steel pipe."
The autopsy temperature was measured deep in the rectum. When the electronic thermometer reading stabilized at 21°C, Zhang Lin drew a horizontal line on the autopsy record. "Ambient temperature 24°C, core body temperature 21°C, temperature difference 3°C," he said, referring to the Henssge autopsy temperature equation table. "Based on the normal rate of body temperature decline, the time of death should be 72-96 hours, but the low temperature environment of the air-conditioned environment will slow down the cooling, requiring a correction factor of 0.8." Xiao Lin suddenly pointed to the elbow joint of the corpse: "Rigidity has been relieved by 60%, the jaw joint can move 3cm, and the wrist joint is completely relaxed. These are characteristics of death 4-5 days under normal temperature, but the low temperature will slow down the relief of rigor mortis."
“Based on comprehensive assessment,” Zhang Lin’s scalpel made a precise Y-shaped incision on the corpse’s chest. The blade hissed as it cut into the skin, revealing subcutaneous fat that rolled outwards like frozen butter, its edges gleaming like pearls. He gently parted the fat layer with hemostats, exposing the pectoralis major muscle beneath. The muscle fibers were grayish-red from decomposition, like a specimen preserved in formalin. “The time of death should be between 8 p.m. on July 3 and 2 a.m. on July 4,” he said, his fingers tracing the muscle texture. “It’s 12 hours earlier than estimated by body temperature alone, because the 24°C environment from the air conditioning is equivalent to 18°C in its natural state, slowing down the decomposition process by 20%.”
Xiaolin was measuring the thickness of the fat layer with electronic calipers. When the reading stabilized at 2.3 centimeters, she looked up and asked, "Professor Zhang, how is this temperature correction factor calculated?" Zhang Lin pointed to the incubator next to the dissection table, which simulated the air-conditioned environment of the scene: "We've done a control experiment. At a constant temperature of 24°C, the reproduction rate of putrefactive bacteria on a corpse is 35% slower than at 28°C, but 15% faster than at 16°C. Taking the middle value, that's a 20% slowdown rate." He asked Xiaolin to extract a piece of pectoralis major muscle tissue, "store it in a 4°C refrigerator, and then do a sarcoplasmic reticulum calcium ATPase activity test. The activity of this enzyme decreases linearly with time of death, accurate to the hour."
The scalpel continued to penetrate, separating the junction of the sternal manubrium and clavicle under the blade, revealing the white costal cartilage. "Look at the degree of cartilage calcification here," Zhang Lin pointed to the ossification center of the costal cartilage with a probe. "The ossification rate of the third rib is 65%, and the fourth rib is 58%, which is within the normal range for a 35-year-old male. However, the subperiosteal hemorrhage has already begun to hemolyze, and the hemoglobin has diffused to a range of about 0.5 cm, which would take about 36 hours at 24°C." He compared it to a standard atlas. "At room temperature, this diffusion range would take at least 48 hours, further proving that low temperature delayed putrefaction."
Zhang Lin picked up the test tube containing vitreous humor and gently shook it under the operating light. The liquid was pale yellow and clear. "The potassium ion concentration in the vitreous humor is 6.2 mmol/L," he said, looking at the test report. "Under normal circumstances, it rises by 0.13 mmol/L per hour after death. Based on this rate, the time of death should be around 72 hours. However, in a low-temperature environment, the release rate of potassium ions will slow down. The corrected concentration corresponds to a time of death of 48 hours, which falls exactly in the range of the evening of July 3rd to the early morning of July 4th."
Kobayashi suddenly pointed to the corpse's cornea, where a network of putrefied veins on the conjunctiva spread like red tree branches. "The corneal opacity is grade two," she observed with a slit lamp. "The pupillary area is slightly cloudy, but the iris texture is still visible, which is characteristic of death 36-48 hours after 24°C. At room temperature, grade two opacity usually appears between 24-36 hours, which also indicates that low temperatures slow down corneal changes." She plotted a corneal change curve on the recording board, with the horizontal axis representing the time of death and the vertical axis representing opacity. The curve shifted significantly to the right at 24°C.
“There’s also livor mortis,” Zhang Lin turned the body over. The livor mortis on the back was dark purplish-red and did not completely fade after being pressed. “It’s distributed on the back, buttocks, and back of the limbs, which is consistent with the characteristics of the transition from the deposition stage to the diffusion stage. In a 24°C environment, this process takes 36-48 hours, while at room temperature it will enter the diffusion stage in 24 hours.”