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

Measuring rectal temperature is a crucial step in determining the time of death. Zhang Kai inserted the probe of the electronic thermometer 15cm into the rectum. The numbers on the display slowly fluctuated, eventually stabilizing at 18.5℃. "Based on the river water temperature of 15℃, the temperature difference is 3.5℃," he calculated using the revised formula for cadaveric reflux. "Considering the special characteristics of the aquatic environment, and assuming a temperature drop of 0.55℃ per hour, combined with rigor mortis and the degree of putrefaction, the time of death should be 30±4 hours, which is between 10 PM on June 13th and 2 AM on June 14th." Xiao Lin suddenly pointed to the fingertips of the corpse: "The fingernails are clearly cyanotic, the nail beds are bluish-purple, and there are pinpoint hemorrhages under the conjunctiva. These should be signs of asphyxiation, right?"

The neck dissection revealed crucial clues. Zhang Kai gently separated the neck skin with hemostatic forceps, revealing a complete fracture on the left side of the greater horn of the hyoid bone, with sharp ends and slight callus formation. "A complete fracture of the hyoid bone is an important sign of mechanical asphyxiation," he measured the length of the fracture line. "The severity of the fracture indicates a large force applied, possibly caused by strangulation or ligation." Deep muscle bleeding in the neck tissues was even more convincing—patchy bleeding in the sternocleidomastoid and omohyoid muscles, dark red in color with clear edges: "This muscle bleeding occurred ante-death, consistent with the force characteristics of strangulation, and the large area of ​​bleeding suggests a prolonged asphyxiation process."

"So what exactly was the method of asphyxiation?" Xiao Lin handed over a magnifying glass, and Zhang Kai found important traces on the bruises on the neck: "Look here, there are roughly circular indentations, 1-1.2 cm in diameter, spaced 2.5-3 cm apart," he pointed to the direction of the indentations, "extending from the left jaw to the right neck, in an incompletely closed state, more like finger marks from strangulation than the grooves of a ligature." The epidermis at the indentations was quite eroded, and dense bleeding points were visible in the dermis, which is a typical reaction to life. There were also skin abrasions between some of the indentations, indicating that there was a struggle.

During the thoracic dissection, the condition of both lungs further confirmed Zhang Kai's judgment. There were obvious hemorrhages in the upper lobe of the left lung and the lower lobe of the right lung, scattered like red millet grains. "Tardieu spots, typical lung changes in asphyxiation," he explained, cutting open the lung tissue. The cut surface was dark red, and colorless foamy fluid oozed out when squeezed. "Accompanied by mild pulmonary edema, indicating that the asphyxiation process lasted for a certain period, consistent with the pathological characteristics of strangulation." There were also a few hemorrhages under the epicardium on the surface of the heart. The muscle tissue of the left ventricular wall was normal in color, without the pathological changes of myocardial infarction, but there was a small amount of bleeding between the myocardial fibers.

The examination of the stomach contents provided supporting evidence for the time of death. Zhang Kai opened the stomach cavity, which contained approximately 200ml of semi-digested food, including rice grains, meat fibers, and vegetable residue. The degree of digestion indicated that the last meal was 4-5 hours before death. "The food residue had no unusual odor, and the pH was 3.7, consistent with a normal gastric acid environment," he said, extracting a sample with a pipette. "No common toxic substances were detected, but a detailed toxicological analysis is needed." A small amount of chyme was found in the duodenum, indicating that digestion was proceeding normally. Combined with rectal temperature, the last meal was estimated to have occurred around 6 PM on June 13th.

When the scalpel made its way to the head, the skull was in a generally normal state. There was a 2×3cm subcutaneous hematoma on the left side of the top of the head; the corresponding outer table of the skull showed no fracture, indicating a minor blunt force injury. "This is a non-fatal injury caused by blunt force trauma," he measured the hematoma's extent. "The impact was relatively minor, likely caused by a collision during the struggle for asphyxiation; it's not the primary cause of death." The skin at the hematoma site showed contusions but no lacerations, indicating the impact was not severe and had minimal impact on the process of death.

“Teacher Zhang, look at the deceased’s hands,” Xiao Lin suddenly pointed to the corpse’s palms. “There are multiple areas of skin abrasion and bruising on the palms and fingertips, and there are fiber residues under the fingernails.” Zhang Kai used a probe to examine the fingernails and extracted a small amount of black fiber and skin tissue. “These injuries were formed before death and are consistent with the characteristics of a struggle. The fiber and skin tissue under the fingernails need to be analyzed for DNA and composition; perhaps we can find the suspect’s biological information.” He noticed that the nail of the deceased’s right index finger was broken, with an irregular end and fresh bleeding at the edge, further confirming that a struggle had taken place before death.

The clothing inspection revealed crucial clues. The collar of the black polyester jacket had a tear, with uneven edges, suggesting it had been violently ripped. "The tear in the collar went from left to right, consistent with the force characteristics of being pulled from the left," Zhang Kai measured the tear length. "The fibers at the tear showed obvious stretching and breakage, indicating a tear made before death." A small amount of river mud and debris from aquatic plants was found in the jacket's left breast pocket, consistent with the composition of the soil from the North River bank, indicating that the body had rubbed against the riverbed while in the water.

"Based on these findings, the cause of death can be basically determined," Zhang Kai told Xiao Lin. "Mechanical asphyxiation, specifically strangulation. The deceased clearly resisted before death, as evidenced by the injuries to the palms and the residue under the fingernails." Xiao Lin asked doubtfully, "Then why was the body found in the river? Was it dumped after death or did the body fall into the water before death?" Zhang Kai pointed to the mouth and nose of the body: "There was a small amount of mushroom-shaped foam in the mouth and nose, and a small amount of drowning fluid in the trachea and bronchi, but there were no typical signs of drowning, such as alveolar dilation or drowning fluid in the stomach. This indicates that the body was dumped into the river after death, and a small amount of liquid entered the respiratory tract after falling into the water, but it was not drowning."

While reviewing the autopsy results, Zhang Kai and Xiao Lin discussed the case. "The time of death was determined to be between 10 PM on June 13th and 2 AM on June 14th, which basically coincides with the drag marks found at the scene," Zhang Kai summarized. "The deceased had engaged in a fierce struggle before death, and there was a physical altercation with the murderer. The skin tissue under the fingernails likely came from the suspect, which is important biological evidence. The finger marks on the neck indicate that the murderer used his right hand to strangle the victim, with a knuckle width of about 2.8 cm, suggesting a male and strong hand."

Looking at the photo of the finger marks on the neck, Xiao Lin said, "Judging from the distribution and pressure of the marks, the killer must have been taller and stronger than the victim; otherwise, it would be difficult to create such obvious finger marks and a fractured hyoid bone." Zhang Kai nodded in agreement: "Combined with Yang Sen's footprint analysis, the suspect's height is 178-183cm, which matches this assessment. Furthermore, the victim's stomach contents were normal, showing no signs of poisoning, ruling out the possibility of being drugged before being murdered; it was a sudden attack." He suddenly pointed to the fibers on the jacket: "These black polyester fibers match those found at the scene, further confirming that the victim was murdered near the North Riverbank and then the body was dumped." (End of Chapter)