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

Zhang Kai examined the skull base and found no fractures in the anterior cranial fossa, middle cranial fossa, or posterior cranial fossa. The cribriform plate was intact, ruling out death from craniocerebral injury.

“Toxicological test sample collection,” Zhang Kai listed, “50 ml each of heart blood, urine, and gastric contents, and 10 grams each of liver and kidney tissue.” He cut open the gallbladder, and the bile inside was golden yellow: “The bile viscosity is normal, and no silt-like stones were found.” When the scalpel pointed to the deep tissue corresponding to the ligature marks on the neck, extensive bleeding was found in the sternocleidomastoid muscle and the infrahyoid muscle group: “The bleeding area in the neck muscle group is 5×6 cm. No fracture was found in the greater horn of the hyoid bone, but there is a tear in the thyrohyoid membrane,” he said with certainty, “This is a typical characteristic of mechanical asphyxiation caused by strangulation. The ligature marks are a post-mortem camouflage.”

"The cause of death has been determined to be mechanical asphyxiation (strangulation), which requires comprehensive verification from both the morphology of the neck injury and the signs of asphyxiation." Zhang Kai picked up a scalpel, the blade moving among the neck muscles, separating the bleeding area deep in the sternocleidomastoid muscle. "You see, this 4×5 cm area of ​​muscle bleeding is diffuse, with obvious tear marks between the muscle fibers. This is a characteristic injury caused by the violent contraction of the muscles in response to external pressure on the neck." He used a probe to lift the muscle bundles in the center of the bleeding area, "especially the sternohyoid and thyrohyoid muscles, where the bleeding is more severe than the surrounding muscle groups, consistent with the point of force applied by the thumb during strangulation."

Xiaolin adjusted the angle of the operating light, focusing the beam above the thyroid cartilage: "Although there is no fracture in the greater horn of the hyoid bone, there is a crescent-shaped hemorrhage under the periosteum, about 1.2 centimeters long, with bone contusions at the edges." She used tweezers to lift the periosteum, and the pale red bleeding point was particularly clear on the grayish-white bone surface. "This subperiosteal hemorrhage is more telling than a fracture, suggesting that the applied external force was continuous compression rather than instantaneous violence, which is consistent with the force characteristics of strangulation—the murderer likely used both thumbs to press on the neck, while the other four fingers tightened forcefully behind."

Zhang Kai's scalpel turned to the common carotid artery. When the vessel was longitudinally dissected, the intima appeared smooth and grayish-white: "The arterial intima is intact without tearing, ruling out neurological reflex death caused by compression of the carotid sinus." He pointed to the dark red blood in the vessel lumen, "but upon closer inspection, flocculent deposits formed by the aggregation of red blood cells can be seen, which is a hemorheological change caused by slow blood flow and hypoxia during asphyxiation." The changes in the venous system were even more obvious, with dilation of the proximal end of the internal jugular vein and thinning of the vessel wall, "a typical manifestation of obstructed venous return, completely consistent with the anatomical changes caused by compression of the neck."

“Now let’s look at the signs of asphyxiation,” Zhang Kai said, flipping open the deceased’s eyelids. The conjunctival surface was covered with pinpoint hemorrhages, so dense they looked like a handful of red peppercorns. “The hemorrhages on the bulbar and palpebral conjunctiva were diffusely distributed, not limited to the fornix. This is one of the specific signs of death from asphyxiation, caused by a sudden increase in intrathoracic pressure and rupture of small blood vessels.” He measured the diameter of the hemorrhages with a ruler. “They averaged 0.3 millimeters, were uniform in size, and were consistent with the microvascular damage characteristics of acute asphyxiation.”

When the scalpel cut open the thoracic and abdominal cavities, the hemorrhages on the surface of both lungs were equally striking. "The punctate hemorrhages under the pleura are consistent with the morphology of conjunctival hemorrhages," Zhang Kai said, lifting the left lung. The cut surface was dark red, and the foamy fluid that overflowed when squeezed had a faint blood-like tinge. "Mucus plugs were formed in the bronchial lumen, and under the microscope, sloughed ciliated epithelial cells could be seen. This is a result of increased secretion of respiratory mucosa during asphyxiation." The subepicardial hemorrhages on the surface of the heart were distributed in a chain, running around the coronary arteries. "This 'angel's kiss' hemorrhage pattern is a classic cardiovascular change in mechanical asphyxiation."

Zhang Kai was exceptionally meticulous in examining the deep tissues of the neck. “There were scattered hemorrhages under the thyroid capsule,” he said, cutting open the thyroid tissue to reveal a reddish-brown cut surface. “This is passive bleeding caused by obstruction of venous return from the thyroid gland when the neck is compressed.” Even more crucial findings came from the larynx: the epiglottic mucosa was congested and edematous, and the glottis was blocked by one-third of the swollen mucosa. “The laryngeal edema reached grade II, and there was localized erosion of the arytenoid cartilage mucosa. These are direct evidence of the reflexive closure of the glottis and the sudden increase in airway resistance during strangulation.”

He suddenly pointed to the deceased's mouth and nose: "There were contusions on the nasal mucosa and the inner mucosa of the lips. Although the injuries were minor, the vital signs were obvious." A small amount of bloody discharge was visible when the oral vestibule was wiped with a cotton swab. "This suggests that the deceased struggled violently while being strangled, attempting to breathe through their mouth, which caused friction damage between the lips and the assailant's fingers or wrist." Combined with the parallel scratches on the forearm, a complete chain of evidence of resistance was formed: "From the contusions to the oral mucosa, to the defensive scratches on the forearm, and then to the bleeding in the deep muscles of the neck, a complete chain of evidence of a struggle before death is established."

Regarding the falsified nature of the ankle ligature marks, Zhang Kai presented three key pieces of evidence: "First, the epidermal abrasion at the edge of the ligature mark is superficial, without corresponding subcutaneous bleeding, and the vital signs are weak; second, the muscle tissue corresponding to the ligature mark shows no contractile bleeding, and no damage to tendons or bones is observed; third, the direction of the ligature mark does not match the area of ​​pressure on the corpse, showing an angle deviation indicating deliberate dragging." He used tweezers to pick up the skin at the ligature mark, "and by comparing it with the epidermal abrasion morphology of the neck strangulation mark, a clear difference can be found—the epidermis and dermis of the strangulation mark are loosely connected, accompanied by blister formation, while the ankle ligature mark is only a superficial mechanical abrasion of the epidermis."

Finally, Zhang Kai placed the neck injury atlas alongside the list of signs of asphyxiation: "Deep muscle bleeding in the neck, subperiosteal hemorrhage of the hyoid bone, and glottic edema constitute the specific injury triad of strangulation; while conjunctival hemorrhage, subpleural hemorrhage of the lungs, and non-clotting of cardiac blood form the complete set of signs of death by asphyxiation. These two sets of evidence corroborate each other, ruling out other causes of death such as poisoning and disease, and clearly pointing to the conclusion of mechanical asphyxiation (strangulation)." He closed the autopsy record book, the soft click of the metal buckle particularly clear in the quiet autopsy room. "As for the ankle ligature marks, they seem more like a clumsy disguise made by the murderer to cover up the real cause of death, which instead exposes their ignorance of forensic medicine."

While Xiaolin was sorting the samples, Zhang Kai suddenly pointed to the deceased's right fingernail: "There are skin tissue fragments under the fingernails." He rinsed them with saline solution, "Extract DNA samples and compare them with biological samples from cigarette butts and fibers at the scene." The clock in the autopsy room pointed to three in the morning. Moonlight from outside the window shone through the blinds, casting long, thin shadows on the autopsy record sheet. The densely packed terms and data were gradually piecing together the deceased's final encounter.

While Zhang Kai was performing the autopsy, Zhang Hui was arranging for people to compare the information with the missing persons database. (End of Chapter)