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

"Secondly, there was a size 39 women's leather shoe print, parallel to the men's shoe print, with a stride length of 55 centimeters and the toes pointing towards the body. The metal fragments on the heel were consistent with the material of the Tiffany earrings. Thirdly, there were incineration residues, including components of 92-octane gasoline, carbonized pine branches, and fragments of a dark blue windbreaker. The fiber composition initially matched the jacket Zhang Lihui was wearing when he disappeared."

He suddenly pointed to the corner of the model: "The most crucial thing is the tire tracks on the ridge. They're 18 centimeters wide and spaced 1.2 meters apart, which belongs to the tire treads of an agricultural tricycle. There are three characteristic cracks on the tread, which perfectly match the tire tracks found at the mine entrance. Combined with the 120-meter drag marks from the valley to the mine, we can deduce that the murderer used a tricycle to move the murder weapon after committing the crime." Veteran detective Zhou Jianguo suddenly interjected: "An agricultural tricycle is too conspicuous. Why not choose a car?" Yang Lin pulled up a high-resolution photo of the tire tracks: "The road from the mine to the valley is too narrow, only tricycles can pass through, and this kind of vehicle is very common in mountainous areas, so it's not easy to attract attention."

Zhang Kai opened the autopsy report, the table estimating the time of death casting a clear shadow on the screen. "The deceased, Zhang Lihui, was ultimately determined to have died between 10 PM on May 12th and 2 AM on May 13th," he circled the key data in red pen, "18-30 hours after correction for grade 5 corneal opacity, 24-30 hours after correction for complete relief of rigor mortis, the degree of digestion of gastric contents corresponding to 4-6 hours post-meal, and considering the delaying effect of low temperature environment (15℃ in the mountainous area at night) on putrefaction, the final error was controlled within 4 hours."

He paused, pointing to a photograph of the hemorrhage on the left ventricular wall: "The cause of death involves multiple factors. A carboxyhemoglobin saturation of 34.7% is not fatal, but the cyanide concentration detected in the blood was 0.8 mg/L, reaching the lethal dose threshold. The soot and charcoal dust in the trachea prove it was from burning before death. Heat-induced respiratory syndrome combined with cyanide poisoning is the true cause of death." Young police officer Xiao Zhao suddenly raised his hand: "Teacher Zhang, which takes effect first, cyanide or carbon monoxide?" Zhang Kai pulled up the toxicology report: "Cyanide inhibits cytochrome oxidase, leading to tissue hypoxia. Combined with the mechanism of action of carbon monoxide, this accelerates the death process by 50%, explaining why a carbon-oxygen concentration of 34.7% can cause rapid death."

Wang Shuai opened the interrogation record of the complainant, Li Fenghuai. The wool fiber specimen from the sheepskin coat gleamed white in the evidence bag. "There are three key points in Li Fenghuai's testimony," he underlined with his pen in the record, "Nothing unusual was found when he took shelter from the rain in the mountain hollow on the afternoon of May 12; he witnessed smoke coming from the mountain hollow at 5:15 a.m. on the 13th; when the body was found, the fire was distributed in a ring, like deliberately piled pine branches." He suddenly pointed to the annotation at the edge of the record: "But he mentioned that 'the iron barrel was burned to only half its original size.' The inner wall of the iron barrel we found in the ashes contained trace amounts of cyanide in addition to gasoline residue—this indicates that the accelerant and the poison may have been contained in the same container."

Zhang Hui projected the CCTV footage of Zhang Lihui's luxury store onto the screen. At 10:05 PM on May 12th, he walked out of the store wearing a dark blue windbreaker, the stainless steel watch on his left wrist gleaming coldly under the lights. "The identification of the deceased is based on four hard indicators," he said, swiping his finger across the screen one by one. "Dental records show root canal treatment on the lower left second molar, which perfectly matches the shape of the filling found in the autopsy; the brand and model of the stainless steel watch on his left wrist are consistent with the photos Zhang Lihui posted on social media; the leather fibers under his fingernails are the same as those in the LV leather goods sold in his store; the preliminary DNA comparison shows a 99.9% match, and the accurate report is pending."

He pulled up the call log's bar chart: "The last caller's number ended in 6789, and there were four calls on May 12th, three of which were between 8 PM and 10 PM, matching the timeline of an 'important appointment.' This number is registered under a canceled ID card, but cell tower location data shows that the signal was present near Wolf Valley between 10 PM and 11 PM on May 12th." Lu Chuan suddenly tapped the table: "Could this number belong to that female companion? The owner of the size 39 shoe print?"

By noon, the sunlight had climbed over the windowsill, casting swaying shadows of trees on the ground. "I think it was someone we knew," Zhou Jianguo said, his cigarette butts piling up in the ashtray. "Zhang Lihui went to the meeting willingly and even got into the other person's car, which shows he trusted them. But there were no signs of a violent struggle at the scene, and his watch chain was intact—if it were a kidnapping by a stranger, the watch would have been ripped off long ago." Zhang Hui added, "Luxury goods store owners have complicated relationships with people. That 'important meeting' might involve illegal transactions, such as the circulation of counterfeit goods or money laundering; otherwise, they wouldn't have chosen a remote mountain village."

Wang Shuai suddenly opened Li Fenghuai's supplementary statement: "He said that on the evening of May 12, he heard a clanging sound of metal coming from the valley. At the time, he thought it was a wild boar rooting in the rocks. Now that I think about it, it might have been the murderer piling up loose branches or moving iron barrels." Yang Lin pulled up photos of the inside of the mine: "We found a bloodstained rag deep in the mine. The DNA test matched Zhang Lihui's, and it was also stained with gasoline and pine wood chips—this should have been used by the murderer to wipe his tools."

Zhang Kai's scalpel seemed to still be flashing before my eyes: "Cyanide poisoning is a quick death, from ingestion to respiratory arrest in no more than 10 minutes, but the murderer still burned the body, indicating that he not only wanted to kill but also destroy the evidence. This dual approach suggests either deep hatred or a fear that the body would reveal certain characteristics—such as specific wounds or identifying features." He suddenly pointed to Zhang Lihui's right hand: "The deceased's right ring finger had old callus on the second joint, left from a fracture three years ago. The murderer may not have known this feature, which is why he wanted to completely burn the body."

Lu Chuan slammed the enamel mug down on the table, tea stains splashing onto the title of "Next Steps in the Investigation." "First, investigate the owner information for the phone number ending in 6789, focusing on Zhang Lihui's business partners and female associates, especially women wearing Tiffany earrings and size 39 shoes; second, trace the origin of the agricultural tricycle, visiting five villages around Wild Wolf Valley and comparing the characteristic cracks in the tires; third, thoroughly investigate the operation of the Starlight Luxury Store, especially whether there are counterfeit goods sold or abnormal fund flows, looking for potential conflicts of interest."

As the meeting adjourned, Yang Lin's investigation notebook was filled with new items to be investigated, Zhang Kai's autopsy report had the words "source of cyanide" circled repeatedly, and Wang Shuai had marked "mining tools need to be investigated" next to "metallic clanging sound." The smoke in the meeting room gradually dissipated, and in the dappled sunlight filtering through the blinds, one could almost see Zhang Lihui's last figure emerging from the luxury store, his dark blue windbreaker gleaming under the streetlights, walking towards the ravine that had swallowed him. (End of Chapter)