The crackdown on organized crime began with the arrest of the mother-in-law.

Chapter 1002 Clues from the Autopsy

“It looks like Kevlar.” He zoomed in on the image. “This high-strength fiber is often used in industrial protective gloves.” But the two quickly realized that these few thin threads alone were not enough to pinpoint the killer. As dusk deepened, the investigation lights under the bridge stubbornly shone, illuminating the silent testimonies waiting to be deciphered.

After the two men finished their investigation, the body was transported back to the Criminal Investigation Division.

The operating lights in the autopsy room illuminated the operating table brightly. Zhang Lin put on medical goggles, the rubber gloves clanging against the metal instruments. The smell of formalin mingled with the cold air, filling the air. The deceased lay flat on the stainless steel autopsy table, his face severely deformed from blunt force trauma, the exposed skin displaying dark purple lividity.

"First, determine the time of death." Zhang Lin picked up a rectal thermometer; the reading was 24°C. He compared it to the temperature change chart on the wall. "The room temperature is 18°C; the temperature drop in the body matches the formula's calculation." His assistant, Xiao Li, quickly recorded the data. Zhang Lin continued to turn the body over, observing the degree of rigor mortis relief. "The rigor mortis in the jaw joint has completely subsided, and the large joints have partially subsided. Considering the corneal opacity, the time of death is between 36 and 48 hours."

The moment the scalpel sliced ​​open the chest and abdominal cavity, the distinctive stench of internal organs filled the air. Zhang Lin carefully examined the lungs and found obvious congestion and edema: "The deceased did not die from a traumatic brain injury." He lifted the trachea with forceps; the inner wall was covered with a large amount of bloody foam. "Death by suffocation, most likely drowning." He then retrieved a syringe and drew a blood sample from the deceased's right ventricle for diatom testing to confirm whether it was river water from under the bridge.

When analyzing the deceased's age, Zhang Lin first focused on the oral cavity. He carefully examined each tooth with a dental probe; "The wear on the maxillary first molar reached grade 3, and the dentin on the occlusal surface of the mandibular molars was exposed." He instructed his assistant to take microscopic photographs; "The enamel surface showed obvious wear striations. Combined with the amount of tartar buildup, the initial estimate was between 35 and 40 years old."

Next, he removed the deceased's skull and examined the degree of suture healing under a dissecting microscope. "The anterior third of the coronal suture had healed, and the parietotemporal suture had begun to ossify." He compared this to a database; "This characteristic matches the physiological changes of someone around 38 years old." When the pelvis was dissected, the features of the pubic symphysis surface provided new clues; "The central ridge of the symphysis surface disappeared, and the ossified nodules on the lateral margins were prominent, a typical feature of someone between 38 and 42 years old."

During the skeletal examination, Zhang Lin paid particular attention to the ribs and clavicle. He used calipers to measure the bone density of the ribs; "The cortical thickness of the 4th to 6th ribs was 0.8 cm, consistent with the characteristics of a middle-aged man." The morphology of the sternal end of the clavicle was also an important indicator; "Bone spurs and osteophytes at the articular surface margins suggest an age of over 38."

To determine age more accurately, Zhang Lin decided to use radiocarbon dating. He took a small sample of bone tissue from the femur. "The carbon-14 content in human bones is in balance with that in the atmosphere. By detecting its decay rate, the individual's birth year can be estimated." The sample was carefully sealed and sent to a specialized laboratory.

While examining the deceased's limbs, Zhang Lin discovered an unexpected clue. The deceased's right little finger showed signs of an old fracture healing, and X-rays revealed complete callus formation along the fracture line; "This fracture occurred at least three years ago." He carefully compared the bone growth and repair, concluding that "the fracture reduction was not ideal, indicating that proper treatment may not have been received at the time."

The autopsy lasted nearly four hours. Zhang Lin took off his gloves and wiped the sweat from his forehead. "It's currently confirmed that the deceased was a male between 38 and 40 years old, who died of mechanical asphyxiation, most likely drowning." He pointed to the organs on the autopsy table, "Once the diatom analysis results are in, we can confirm whether the deceased died in the river under the bridge."

Before leaving, Zhang Lin examined the deceased's teeth again. Under ultraviolet light, the filling in one molar emitted a faint fluorescence; "This is a resin material that has only been widely used since 2015." He immediately contacted the forensic department and "retrieved treatment records from dental clinics throughout the city from 2015 to the present, focusing on screening males aged 35 to 40 who had undergone molar filling treatment and had an old fracture of the little finger on their right hand."

As dawn broke through the clouds, the Criminal Investigation Division's conference room was already packed. Li Ming stood in front of the whiteboard, heavily circling the words "Chengxi Bridge Hole Murder Case" in red pen. Photos from the scene were playing on a loop on the projection screen, the cold white light reflecting on the tired faces of the attendees.

"Let's begin the report." Li Ming's voice broke the silence, his fingertips tapping the whiteboard. "Xiao Yang, start with the on-site investigation."

Xiao Yang opened the thick investigation report, and the projector switched to a 3D model of the bridge arch: "We conducted a systematic investigation of the scene, collecting 137 sets of photos and 58 pieces of physical evidence." He pulled up a photo of shoe prints, "and found a size 42 work shoe print, but the edges showed obvious dragging and erasing marks, indicating deliberate damage by the perpetrator." The image switched to bloodstained stones, "A small amount of tissue fragments were extracted from the surface of the murder weapon; it has been sent for DNA testing, but no fingerprints were found."

He paused, his voice low: "Grass clippings and fibers were collected from the victim's clothing, but they were all common types. No key evidence pointing directly to the killer was found at the scene, and even a review of surveillance footage yielded nothing—cameras within a two-kilometer radius of the bridge underpass were either malfunctioning or had missing footage during the time of the incident."

"Zhang Lin, what are the autopsy results?" Li Ming turned to the forensic doctor sitting in the corner.

Zhang Lin adjusted his glasses, and the autopsy photos appeared on the screen: "The deceased was a male aged 38-40, the time of death was 36-48 hours ago, the cause of death was mechanical asphyxiation, most likely drowning." He zoomed in on the lung images, "The diatom analysis results showed that the river water inhaled by the deceased contained diatoms unique to the riverbed under the bridge, confirming that he died at that location."

"Explain the criteria for determining age in detail," Li Ming interrupted.

An analysis was conducted based on multiple factors, including tooth wear, cranial suture healing, and pubic symphysis surface characteristics. Zhang Lin retrieved comparative charts showing: tooth wear grade 3, healing of the anterior 1/3 of the cranial sutures, and significant ossification nodules on the pubic symphysis surface. Combined with radiocarbon dating, a preliminary age estimate was approximately 38 years old. Additionally, the deceased had an old fracture in the little finger of his right hand, occurring at least 3 years prior, and had not received proper treatment.

"Xiao Wang, how's the visit going?"

Xiao Wang rubbed his red eyes and opened his notebook: "The shepherd Zhao Deshun, who reported the incident, could only provide limited clues. He only remembered hearing a vehicle engine around 10 p.m. on the night of the incident. We checked 127 households in the surrounding villages; three people claimed to have heard strange noises, but couldn't pinpoint the exact time." He pulled up the surveillance footage and continued his report.