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

"The deceased was a male, aged 40-50, 175cm tall. He died between midnight and 3 a.m. six days ago. The cause of death was mechanical asphyxiation, caused by strangulation with a cotton or linen strip. He had been struck by blunt force, such as stones or wooden sticks, resulting in injuries to his left temporal region and injuries from a struggle. His right palm had abrasions, and there were fibers and mud under his fingernails. He was dumped into the Beihe River one to two days after his death, and may have been exposed to normal temperature conditions on land before being dumped. A piece of brass metal was embedded in his left wrist, possibly from a repair tool. His last meal was between 6 p.m. and 8 p.m. five days ago. No drug residue was found in his stomach, ruling out poisoning. No identification documents or jewelry were found on his body, and his clothing was too soaked and decomposed to identify the brand. His identity needs to be confirmed through DNA comparison or the missing persons database."

Xiao Lin, sorting through the autopsy report, asked with a puzzled look, "Could the tire tracks of the electric bike/motorcycle, the small truck/SUV, and the Yellow Crane Tower cigarette butt found at the scene all point to the same suspect? Could the dark red stain on the metal hook be the victim's blood?" Zhang Kai took the report and added notes at key points: "The two types of vehicle types in the tire tracks likely correspond to the suspect's 'transportation-transfer' process. The small truck was used to transport the body from the land stop to the upper reaches of the Beihe River, and then the electric bike/motorcycle was used to transfer the body to the disposal point. This would avoid large vehicles being spotted on the riverbank and allow for flexible handling of narrow sections of road. If the DNA from the Yellow Crane Tower cigarette butt can be extracted, it can be compared with the skin tissue fragments under the victim's fingernails to confirm whether it belongs to the same person. The dark red stain on the metal hook needs to be examined to determine if it is human blood. If it matches the victim's DNA, it means the hook may have fallen during the struggle and could become key evidence linking the suspect to the scene."

He paused, then continued, "Furthermore, if volcanic rock particles are detected in the mud and sand under the deceased's fingernails, combined with the geological features of the upper reaches of the Beihe River, the upstream source of the body dumping site can be further determined, narrowing down the suspect's activity range; if the brass metal fragments can be identified as coming from specific repair tools, it can be inferred that the deceased's occupation may be related to mechanical repair or construction, providing direction for identity investigation."

As the body was resealed and sent to the cold storage, Zhang Kai removed his gas mask, his forehead already drenched in sweat. He looked at the autopsy report and the specimen bottles filled with various samples on the table; every piece of data had been repeatedly checked, and every conclusion had clear pathological evidence. "Send these samples to the technical department immediately, prioritizing testing for metal fragments, fiber materials, cigarette butt DNA, stains on metal hooks, and geological components of mud and sand," Zhang Kai instructed Xiao Lin. "In addition, synchronize key information such as the time of death, cause of death, and time of body disposal with Team Leader Lu, so they can adjust their investigation direction, focusing on 'owners of small trucks and electric vehicles/motorcycles active in the early morning of the 6th day' and 'missing persons related to the repair or construction industries'."

Xiao Lin quickly left the autopsy room with the evidence and report, while Zhang Kai remained, lost in thought, staring at the crime scene photos beside the autopsy table. The canvas bag, metal hook, and cigarette butt in the photos, along with the neck pressure marks, metal fragments, and signs of struggle found during the autopsy, were gradually forming a chain of clues. Although the victim's identity was still unclear, the precise determination of the time of death, cause of death, and the process of disposing of the body had already provided a clear direction for solving the case. He firmly believed that as long as the technical department could find relevant evidence from the evidence, combined with the investigators' screening, they would eventually identify the suspect and bring the truth of this Beihe River floating corpse case to light.

At this moment, in the conference room of the Criminal Investigation Detachment, Lu Chuan had received Zhang Kai's preliminary autopsy report. Looking at the key information on the report—"mechanical asphyxiation," "strangulation," and "post-mortem disposal"—he tapped his fingers lightly on the table, then dialed Wang Shuai's number: "Immediately adjust the focus of the investigation. First, focus on the whereabouts of small trucks and electric vehicles/motorcycles in the upper reaches of the Beihe River in the early morning of six days ago, looking for clues that match 'both types of vehicles belong to the same person or the same gang'; second, investigate men aged 40-50 who have gone missing in the past week, especially those in the repair and construction industries, focusing on DNA comparison; third, expand the investigation area in the upper reaches of the Beihe River, looking for possible land stops and fight scenes, and be sure to make a new breakthrough within 48 hours!"

As night deepened, the lights in the autopsy room remained bright. Zhang Kai organized the autopsy records, prioritized all the samples for testing, and sent them to the technical department. He knew that this autopsy, a battle against water and time, was only the first step in solving the case; subsequent evidence comparison and investigation would be key to uncovering the truth. But he was confident that, with precise autopsy findings and meticulous analysis of clues, this crime hidden beneath the calm surface of the river would ultimately be illuminated by the sunlight of justice.

As soon as Zhang Kai's autopsy report reached Zhang Hui, he led five team members into the missing persons verification office of the Criminal Investigation Detachment. The clock on the wall pointed to 8 p.m., the air conditioner vents in the office emitted a slight hum, and six computer screens lit up simultaneously, the blue light reflecting on everyone's tired faces. According to the autopsy results, the deceased was a male aged 40-50, about 175cm tall, who died in the early morning of six days ago, possibly working in the repair or construction industry. He had been wearing a tool-like ornament containing brass fragments on his left wrist. These characteristics became the core basis for their information screening.

"Is this system even going to work? Each filter takes three minutes. With over 1000 records, how long will it take?" Team member Xiao Chen complained, staring at the slowly loading progress bar on the computer screen. He repeatedly clicked the mouse, as if trying to speed things up. Two cans of instant coffee on the table were already empty, with brown stains at the bottom of the cups. "My eyes are practically turning into panda eyes. I'm running around to different sites during the day, and then I have to stare at this screen at night. If this keeps up, I'm afraid I'll just collapse right here."

Zhang Hui handed a cup of freshly brewed hot tea to Xiao Chen: "Bear with it. The key now is identifying the deceased. If we can't find their identity, all the subsequent investigations will be in vain." He rubbed his aching shoulders, his voice slightly hoarse from continuous high-intensity work. "Everyone, refine the screening criteria again. Age should be 40-50 years old, height 173-177cm, disappearance time 6-8 days ago, and the occupation should include keywords like 'repair,' 'construction,' or 'work.' Pay special attention to whether anyone mentions 'carrying tools' or 'wearing metal jewelry.'"

Team member Xiao Li slumped back in his chair, which creaked in protest. "Detailing it won't help," he said, stretching, his bones clicking. (End of Chapter)