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

Chapter 1291 Characteristics of Death by Mechanical Asphyxiation

The diagnosis of mechanical asphyxiation requires multifaceted evidence; pulmonary edema alone is insufficient. Zhang Lin set aside the lungs and began dissecting the neck. He used a scalpel to dissect the skin, muscles, and fascia of the neck layer by layer, carefully examining the condition of each tissue. When the scalpel reached the left sternocleidomastoid muscle, he suddenly stopped, picking up a piece of muscle tissue with forceps: "Li Ran, look here. There's a clear area of ​​bleeding deep within the left sternocleidomastoid muscle, dark red in color, with well-defined borders. This is muscle bleeding caused by violence before death."

Li Ran leaned closer and, under the cold light, the bleeding area in the muscle tissue was particularly noticeable, forming a stark contrast with the surrounding normal tissue. "Does this mean the deceased's neck was subjected to external pressure before death?" he asked, his eyes filled with eager curiosity. Zhang Lin nodded: "That's right. Continue the dissection and examine the hyoid bone and thyroid cartilage."

The scalpel continued to penetrate deeper, gradually revealing the hyoid bone and thyroid cartilage deep within the neck. Zhang Lin gently moved the hyoid bone with tweezers and discovered a fine fracture mark at the greater horn of the hyoid bone, and a slight deformation at the superior horn of the thyroid cartilage. "A fractured hyoid bone and deformed thyroid cartilage—these are crucial pieces of evidence for strangulation!" Zhang Lin's voice carried a barely perceptible hint of excitement. "The hyoid bone is located in the middle of the neck, protected by muscles and fascia. It only fractures when subjected to significant external force before death. Post-mortem fractures do not involve muscle bleeding, but we have just discovered pre-mortem bleeding in the neck muscles. This forms a complete chain of evidence proving that the deceased died from mechanical asphyxiation caused by strangulation."

To further confirm, Zhang Lin examined the deceased's palpebral and bulbar conjunctiva: "There were scattered bleeding points on the palpebral and bulbar conjunctiva, which is a typical sign of mechanical asphyxiation. During asphyxiation, the body's lack of oxygen causes capillaries to dilate and rupture, forming bleeding points in weak areas such as the conjunctiva. Combined with the bleeding in the neck muscles, the fracture of the hyoid bone, pulmonary edema, and the conjunctival hemorrhage, it can be definitively determined that the cause of death was mechanical asphyxiation, and the weapon used was the suspect's bare hand, that is, strangulation with his bare hand."

At this moment, the toxicology department sent a detailed test report: "Forensic doctor Zhang, no organophosphates or carbamates were detected in the liquid sample from the decomposing body, nor were diazepam, barbiturates, or common poisons such as tetramine and fluoroacetamide detected, ruling out the possibility of death by poisoning."

"Great!" Zhang Lin put down the scalpel, removed his protective mask, and showed a hint of fatigue on his face, but his eyes remained sharp. "The cause of death has been determined to be mechanical asphyxiation, strangulation with bare hands. The time of death was between 7 and 9 pm on the 18th of this month, three days ago. Poisoning and natural death have been ruled out. Now let's combine the autopsy results with the clues from the scene to sort out the case. The suspect had contact with the deceased between 7 and 9 pm three days ago, and then strangled him to death with his bare hands. Afterwards, the suspect drove a stolen 'Jinpeng' brand electric tricycle with the last four digits of the license plate being 36, and transported the body to the bushes near the north side of Beishan Park. Then, he used a red shovel with a cracked wooden handle that he carried with him to dig a shallow pit for Zheng Bin and buried the body in it. During the burial process, the suspect also smoked 'Huanghelou' cigarettes, discarded the cigarette butts at the scene, and finally drove away in the electric tricycle."

Li Ran took out the previous on-site investigation record and pointed to the details: "Teacher Zhang, look, the traces of the electric tricycle found at the scene are consistent with the characteristics of the vehicle driven by the thief, the soil on the shovel has the same composition as the soil in the burial pit, and the brand of the cigarette butt is also consistent with your deduction. This shows that our autopsy results and the clues at the scene are completely consistent, forming a complete chain of evidence!"

Zhang Lin nodded and continued his analysis: "From the autopsy results, we can also deduce some of the suspect's characteristics. Strangling the neck with bare hands requires a certain amount of physical strength, and the ability to control the victim at close range indicates that the suspect is male, physically strong, and likely between 25 and 40 years old. The fact that the suspect was able to accurately locate the secluded burial site in Beishan Park and even stole a car to transport the body beforehand suggests that he was familiar with Beishan Park and its surrounding terrain, and may be a local resident or someone who frequents the area. In addition, the suspect discarded cigarette butts after burying the body and did not deliberately clean up the scene, indicating that he may have had a sense of complacency, believing that the shallowly buried body would remain undiscovered for a long time, or that he was in a state of tension after committing the crime and neglected to handle the traces at the scene."

He paused, his gaze falling on an old scar on the joint of the deceased's right index finger: "The deceased had an old scar about 1 centimeter long on his right index finger, with neat edges, like a healed wound from a sharp object; combined with his work pants and worn cuffs, we can infer that the deceased may have been engaged in manual labor, such as a construction worker, porter, or decorator. This occupational characteristic is very important for confirming the deceased's identity. We can use DNA databases to compare with recently missing manual laborers to quickly find the deceased's identity information, and then trace his social relationships to identify suspects."

While taking notes, Li Ran added, "Also, the deceased's clothing. The dark gray jacket is from a common brand and is readily available on the market. However, we can trace the sales channels of the clothing to identify people who recently purchased this style of jacket. We might be able to find clues related to the suspect. In addition, the residue under the deceased's fingernails is still being tested. If we can detect the suspect's skin tissue or DNA, we can directly identify the murderer!"

Zhang Lin nodded in agreement: "The detection of residue under the fingernails is crucial. Fragments of the murderer's skin may remain under the fingernails of a decomposing corpse, which is important biological evidence. We will then compare the victim's DNA with the residue in the electric tricycle bed and the fingerprints on the shovel handle to further confirm the connection between the victim and the perpetrator, ensuring that every piece of evidence corroborates each other and makes the case investigation flawless."

At 11:30 p.m., the autopsy work was completed. Li Ran sorted and labeled the 23 samples collected and sent them to various laboratories for further testing; Zhang Lin sat in front of the computer in the autopsy room and began to write a detailed autopsy report, sorting out the time of death, cause of death, characteristics of the body, case analysis and other contents one by one, and attaching corresponding autopsy evidence to each conclusion to ensure the scientific nature and rigor of the report.

The cold lights in the autopsy room were still on, illuminating Zhang Lin's focused profile. He knew that this autopsy report was not merely a record of the deceased's death, but also a "map" guiding investigators. The accurate estimation of the time of death could help the police narrow down the scope of their investigation; the determination of the cause of death could pinpoint the suspect's modus operandi; and every sample extracted from the body could become a key to uncovering the truth of the case.