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

“Remove the larynx,” Zhang Kai instructed Xiao Lin to fix the position. “The epiglottic cartilage mucosa is congested and edematous, and there is a small amount of mucus adhering to the glottis.” He used a laryngoscope to examine the tracheal wall: “The tracheal mucosa is smooth, and no foreign body or bloody secretions are seen, ruling out death due to airway obstruction caused by mechanical asphyxiation.” The dissection of the deep tissues of the neck showed that the intima of the common carotid artery was intact and no rupture was found: “There is bleeding in the neck muscle group corresponding to the ligature mark, reaching the muscle layer, which is consistent with the location of the ligature mark on the body surface.”

The examination of the stomach contents made Zhang Kai stop what he was doing. "The stomach volume is about 300 milliliters," he said, drawing up the contents with a pipette. "It contains semi-digested rice, meat fibers, and vegetable residue, and no drug or toxin crystals were found." While taking the sample, Xiao Lin suddenly noticed pinpoint bleeding on the folds of the gastric mucosa: "There are diffuse bleeding points on the gastric mucosa, consistent with the stress response of death by asphyxiation."

“Determining the time of death requires cross-verification of multiple indicators,” Zhang Kai said, picking up the dissection forceps and clamping the deceased’s wrist. When he gently lifted it, the 90-degree angle formed by the forearm and upper arm remained stable. “Rigidity has progressed to all muscle groups, reaching a level three state of rigidity. Look,” he pressed the deceased’s quadriceps muscle with his thumb, leaving only a shallow indentation on the surface of the muscle, which returned to its original state in a few seconds. “The muscle rigidity has increased significantly, and the jaw joint is completely rigid. Even a mouth opener requires moderate force to pry it open. These characteristics are consistent with the behavior of someone who has been dead for 6-8 hours.”

Xiaolin took notes, her pen scratching across the paper: "Rigoletto distribution: It has appeared in the face, neck, torso, and limb muscles, with joint fixation at grade III." She opened the deceased's eyelids, revealing a thin, grayish-white hazy film covering the cornea. "Corneal opacity grade II. When observed with an ophthalmoscope, the pupil outline is blurred but still recognizable, and the light reflex is completely absent—this is more accurate in pinpointing the time window than simple rigor mortis."

Zhang Kai moved his finger to the deceased's fingernail. The nail bed was dark purple and cyanotic, like a mulberry that had been soaked in water: "This is a typical sign of death by asphyxiation, but it can also help determine the time of death." He pointed an infrared thermometer at the fingertip, and the number on the screen remained stable at 24.5℃. "The ambient temperature is 18℃, and the temperature of the fingertip is 6.5℃ higher than the ambient temperature. This temperature difference will gradually decrease after about 6 hours, and usually does not exceed 5℃ after 8 hours. The current data is right in the middle."

He turned and grabbed a rectal thermometer, slowly inserting the probe 6 centimeters into the anus before fixing it in place. "Rectal temperature is currently the most stable indicator of core body temperature," he explained while waiting for the reading. "Skin temperature is greatly affected by the environment, and oral and axillary temperatures are easily distorted. Only rectal temperature can reflect the body temperature at the moment of death." The thermometer beeped, and the number 28°C flashed on the screen.

“Now let’s apply the Henssge post-mortem temperature calculation formula,” Zhang Kai pulled a calculator from his white coat pocket. “First, determine the temperature difference: rectal temperature 28℃ minus ambient temperature 18℃ equals 10℃. Then substitute it into the formula: Time of death (hours) = 3.4 + (37 - rectal temperature) × 1.4 + (ambient temperature - 20) × 0.3.” His fingers flew across the keys. “The calculation process requires a correction factor because the deceased weighed approximately 70 kilograms, which is of medium build; the correction value is 0.8.”

Xiaolin checked the parameters: "The core of the Henssge model is to consider variables such as body size, ambient temperature, and cause of death based on the nonlinear characteristics of the rate of decrease in body temperature. The decrease in body temperature in asphyxiation deaths is slightly slower than in deaths from disease, because there is often a violent struggle before death that leads to increased heat production." She looked at the result on the calculator, "7.2 hours, which is 7 hours after rounding."

Zhang Kai suddenly bent down to examine the deceased's chest skin, gently lifting the skin next to the nipple with a scalpel: "The livor mortis has stabilized and does not fade when pressed." The pale purplish-red spots are distributed in patches on the chest and abdomen with blurred edges. "The distribution location is consistent with the body position, mainly concentrated on the back, buttocks, and uncompressed areas of the limbs. This is a fixed-stage livor mortis that forms 4-6 hours after death, which crosses with the previous indicators."

He used tweezers to pick up the deceased's hair, and the hair follicles at the roots had already begun to separate from the skin: "The hair plucking test was positive, and the hair follicle sheath was easy to fall off, which is also a characteristic of more than 6 hours after death." Kobayashi immediately took a sample and put the hair with the follicle into the preservation solution: "Histological examination of the hair roots can observe the degree of autolysis, as a supplementary basis."

“The state of digestion of the stomach contents can also help verify this,” Zhang Kai recalled the results of the examination. “The semi-digested rice grains still showed intact starch granules, the transverse structure of the meat fibers had partially disappeared, and the cell walls of the vegetable residue had begun to rupture—this is consistent with the degree of digestion 4-5 hours after a meal.” He drew a timeline on the autopsy record sheet. “Assuming the deceased’s last meal was around 7 p.m., then the time of death would be exactly between 0 a.m. and 1 a.m., which perfectly matches the calculated body temperature.”

Finally, he shone a UV lamp on the skin of the deceased's forearm, and tiny green spots were faintly visible on the inside of the wrist joint: "The first green spot appeared, covering an area of ​​about 1×0.8 cm. This is a signal that intestinal bacteria have begun to migrate. It is usually more obvious about 12 hours after death, but early signs can also support our inference."

Xiaolin entered all the data into the computer, and the probability distribution curve of the time of death on the screen showed a clear peak: "The 95% confidence interval is 6.5-7.5 hours, the median is 7 hours, and the error range is controlled within half an hour." She looked up at Zhang Kai, "It perfectly overlaps with the time period inferred from the on-site investigation based on the garage surveillance and security patrol time."

Zhang Kai closed the autopsy record book, the metal buckle making a crisp sound: "The chain of evidence formed by multiple indicators does not lie," he said, taking off his fogged glasses and carefully wiping them with lens paper. "This time of death can not only pinpoint the suspect's crime scene, but also verify the authenticity of the testimony of 'strange noise around 1 a.m.' during the on-site investigation—that could very well be the moment the victim was murdered."

“Now we’ll proceed with the head dissection,” Zhang Kai said, setting up the head frame and making a circular incision in the skull with a circular saw. “The skullcap is 0.5 cm thick, and the bone structure is normal.” Upon opening the cranial cavity, the dura mater was intact: “No subarachnoid hemorrhage was observed. The brain tissue was of medium texture, with shallow sulci and widened gyri, consistent with cerebral edema.” The cerebellar tonsillar herniation reached a depth of 0.8 cm: “The brainstem was significantly compressed, a typical central nervous system change in asphyxiation-related death.”

Xiaolin measured the brain weight: "1450 grams, within the normal range." She took a tissue sample from the hippocampus. "The neurons in the CA1 region of the hippocampus show ischemic changes, consistent with the characteristics of hypoxic-ischemic encephalopathy." (End of this chapter)