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

"The deceased's fatal injury was a single-edged sharp weapon stab wound to the chest—a 2×0.8cm stab wound in the 4th-5th intercostal space on the left side of the sternum, with a wound depth of 6cm, penetrating the left ventricular wall to the right ventricle. There were a large number of blood clots in the ventricular cavity, consistent with the characteristics of death from hemorrhagic shock; the stab wound entrance was spindle-shaped with clean edges, and the wound angles were one blunt and one sharp, suggesting that the weapon used was a single-edged dagger or sharp knife with a blade length of 8-10cm and a width of 2-3cm."

He added, "Besides the fatal wound, the deceased also had two non-fatal injuries sustained before death: one was a 3×2.5cm subcutaneous hematoma on the right forehead with a 0.5cm epidermal abrasion in the center, stained with black soil from the grassland, consistent with being caused by a blunt object such as a stone or stick; the other was a 4×1.5cm epidermal abrasion with subcutaneous bleeding on the left side of the neck, from which black canvas fibers were extracted, consistent with the fiber composition of the cloth held in the deceased's right hand, presumably caused by friction when the suspect covered the deceased's mouth and nose with the cloth. In addition, there were multiple epidermal abrasions on the deceased's right palm, and DNA from male skin tissue fragments extracted from the fingernails has been entered into the system; the nail of the left ring finger was broken, all of which were defensive injuries sustained during the struggle, indicating that the deceased had fiercely resisted the suspect before death."

Next, Yang Lin reported on the on-site investigation. He projected the latest on-site investigation map onto the screen, marking the newly discovered traces with different colored markers: "During the second investigation of the grassland and the surrounding 500-meter area, we made three additional discoveries. First, we extracted more black canvas fibers from the stone wall of the abandoned sheepfold, which are completely consistent with the fabric in the deceased's hand and the fiber composition of the neck injury. The fibers also had a small amount of blood on them, which, after testing, completely matched Zhang Tao's DNA. It is speculated that the suspect had stayed in the sheepfold, and his clothing had rubbed against the stone wall, leaving traces."

He switched to the next photo, which showed the tire tracks of a farm tricycle at the bottom of an irrigation ditch: "Secondly, a complete farm tricycle track was found at the bottom of the dried-up irrigation ditch. The tire treads were horizontal stripes, and the wheel track was 1.2 meters wide, which was completely different from the vertical stripes of the motorcycle tire tracks found earlier. In the pile of rubble next to the track, a mineral water bottle cap of the same type as the one found next to the deceased was found. There were blurry fingerprints on it, which were extracted and identified as male fingerprints. No suspect has been matched in the database yet."

"Third, the size 42 cloth shoe print found on the herder's path was confirmed by a check of nearby herders to belong to Wang Xiulian, a villager from Xiangyang Village. She had gone along the path to the pasture to look for her lost sheep around 7 p.m. on the 15th, and the shoe print was left at that time. It is unrelated to the case and has been ruled out as a suspect." Yang Lin emphasized, "In addition, we also found several size 44 leather shoe prints in the grass on the pasture slope, with a stride length of 88 centimeters, consistent with the previous speculation that the suspect is 180-185cm tall. A small amount of engine oil residue was detected in the soil on the edge of the shoe prints, which may have come from the vehicle driven by the suspect."

Wang Shuai then reported on the investigation around the grassland. A flowchart of the surveillance investigation appeared on the screen, with red dotted lines marking the clues that had been ruled out: "We focused on investigating the surveillance footage of the provincial highways, county roads, and pastoral roads around the grassland from 9 p.m. on August 15 to 2 a.m. on August 16. We found a total of 7 suspicious vehicles—3 black motorcycles, 2 agricultural tricycles, and 2 vans. After verification, all of them have been ruled out as suspects."

"Explain the reasons for the exclusions in detail. Have you found any other suspicious persons' movements?" Lu Chuan asked. Wang Shuai's tone was tinged with regret: "One of the vehicles was a black Honda CB400 motorcycle, owned by Zhao Jianming from Xiangyang Village. He went to a relative's house on the east side of the grassland on the evening of the 15th to deliver farm tools, and he has a complete alibi. Another vehicle was a black farm tricycle with horizontal striped tires, owned by Sun Fugui from Linhe Village. He went to a neighboring village to pick up corn that evening, which can be corroborated by surveillance footage and witnesses. The remaining vehicles were excluded due to 'inconsistent routes' and 'conflicting times.' In addition, we visited 28 herder households in three villages around the grassland. Only two people said they heard arguing in the direction of the grassland on the evening of the 15th, but they did not see any specific people and could not provide any further clues."

He paused, then added, "However, we found a suspicious figure at the highway checkpoint on the west side of the grassland—at 11:30 p.m. on the 15th, a man about 180cm tall, wearing a dark coat, hat and mask, walked along the highway towards the city. Due to the dim lighting, the surveillance cameras failed to capture his facial features. This time period closely matches the time of death, and the route is consistent with the exit of the grassland. It is speculated that he may be the suspect who fled after committing the crime, but we cannot confirm his identity at present."

Zhang Hui concluded by reporting the deceased's identity and related clues. He projected Zhang Tao's social network diagram onto the screen, marking key figures with red lines: "Through interviews with Zhang Tao's family, villagers, and colleagues, we learned that Zhang Tao has a mild personality and a good professional reputation, but there are two recent conflicts that deserve attention. First, the dispute with herdsman Li Jianguo—on the morning of the 15th, Zhang Tao examined Li Jianguo's sheep, diagnosed them with an infectious disease, and recommended culling. Li Jianguo believed that Zhang Tao had misdiagnosed the sheep and refused to take action. The two argued, and Li Jianguo threatened, 'If the sheep die, I won't let you off the hook.'"

“Secondly, there’s the competitive conflict with Zhou Ming, a veterinarian from a neighboring village. Zhou Ming has recently been stealing Zhang Tao’s clients multiple times. The two had a verbal altercation over business, and Zhou Ming privately said, ‘Zhang Tao is blocking my path to wealth; I’ll make sure he gets into trouble sooner or later.’” Zhang Hui’s expression turned serious. “Furthermore, Zhang Tao’s wife, Liu Fang, reported that at 4 p.m. on the 15th, Zhang Tao received a phone call before leaving home. The caller claimed to be a ‘herdsman from the grasslands,’ saying that his sheep had suddenly fallen ill and that he needed to come immediately. Zhang Tao didn’t ask the caller’s name, just grabbed his tool bag and left, and never returned. We suspect that this ‘mysterious caller’ is the suspect, who may have lured Zhang Tao to the grasslands under the pretext of ‘seeing a doctor’ to commit the crime.”

"What is the current situation of Li Jianguo and Zhou Ming? Have you investigated their whereabouts and means of transportation?" Lu Chuan pressed. Zhang Hui nodded: "We have launched an investigation into the two: Li Jianguo was entertaining relatives at home from 7 pm to 12 am on the 15th, and there are 10 witnesses to corroborate this, so he had no time to commit the crime; Zhou Ming was helping a cow give birth in a neighboring village on the evening of the 15th and did not return home until 1 am, so he also has an alibi. However, both of them have agricultural tricycles, and the tire tread pattern of Zhou Ming's tricycle is horizontal stripes, which is consistent with the type of tricycle track found at the scene. Although there is no direct evidence, further verification is still needed."

After the report, a brief silence fell over the meeting room as everyone sorted through the clues. Lu Chuan broke the silence first: "Now all the clues point to one core point—the suspect lured Zhang Tao to the pasture under the pretext of 'sheep disease,' then killed him with a single-edged sharp weapon after an argument. He fled on foot or by vehicle, likely a motorcycle or tricycle; the suspect is 180-185cm tall, male, possesses a single-edged sharp weapon, may be familiar with the veterinary industry or the pasture environment, and had a potential conflict with Zhang Tao, possibly professional competition, revenge for a dispute, or some other undiscovered relationship." (End of Chapter)