eurekapd Chapter 993 The Skeleton Case: First Case Analysis Meeting
Chapter 993 The Skeleton Case: First Case Analysis Meeting
"The bone tissue showed typical pathological changes characteristic of alcoholic bone disease," he pointed to the image on the screen, "and combined with serum calcium and phosphorus metabolism disorder indicators, it was inferred that the deceased had a long history of alcohol abuse."
The specific activity of collagen was determined to be 78.3 ± 2.1 pMC using carbon-14 accelerator mass spectrometry. Combined with the soil humic acid penetration depth of 3.2 mm, and based on the Bass time-of-death model, the time of death was estimated to be 18-24 months prior. "Observe the callus morphology at the rib fracture site." Zhang Lin held up a rib sample; the fracture surface showed characteristics of three-stage healing. "The coexistence of lamellar bone formation at the old fracture site and fibrous callus at the new injury site indicates that the deceased experienced at least two violent injuries before death."
When examining the skeleton numbered GX-2024-017-B, Zhang Lin first used a pelvic sex determination function for calculation. The width-to-depth ratio of the greater sciatic notch was 1.6:1, the pubic arch angle was 102°, and the morphology of the pubic symphysis surface was consistent with female characteristics. Dental measurements showed that the enamel wear on the occlusal surface of the molars reached grade III. Combined with the degree of ossification of the pubic symphysis surface, the age was determined to be between 25 and 30 years old.
The linear fracture at the occipital bone exhibits typical characteristics of a convection injury, with the fracture line extending radially from the point of impact towards the skull base. A "V"-shaped fracture is observed in the lesser wing of the sphenoid bone. According to Duhaime's theory, this fracture morphology is consistent with the deceleration mechanism of a fall from a height. Zhang Lin retrieved the CT 3D reconstruction images, but noted that the indentation at the edge of the piriform foramen of the maxilla, with a width matching the width of an adult's palm, suggests mechanical asphyxiation due to suffocation.
An abnormality was found in the rib examination: a fresh oblique fracture of the right seventh rib, but no bleeding zone or inflammatory reaction was observed at the fracture ends, consistent with postmortem injury characteristics. Metal residue from the fracture surface was subjected to energy dispersive spectroscopy (EDS). Zhang Lin placed the sample under a scanning electron microscope; the EDS spectrum showed an iron content of 82% and a chromium content of 12%, consistent with the composition of common stainless steel knives, suggesting it was a tool used for postmortem mutilation.
Analysis of bone tissue fluoride content revealed a concentration as high as 2800 ppm, far exceeding the normal range (100-300 ppm). "This is a typical manifestation of endemic fluorosis," Zhang Lin stated, displaying bone mineral density data. "The trabeculae show a pathological process of transformation from woven bone to lamellar bone. Combined with the characteristics of dental fluorosis, this can serve as an important basis for identification."
In determining the time of death, Zhang Lin employed a multi-indicator comprehensive analysis: The degree of collagen degradation was measured, calculating the time of death to be approximately 16 months; based on entomological evidence, the blowfly larvae found in the nasal cavity of the remains were third-stage larvae; combined with local insect developmental accumulated temperature data, the time of death should be 15-18 months prior. The rope marks at the wrist bones matched the fiber composition of the denim fabric extracted from the scene, and the wear characteristics observed under a polarized light microscope confirmed that they were caused by binding before death.
As the final test report was printed, Zhang Lin organized the experimental data scattered across the table: Individual GX-2024-017-A, a male aged 35-40, died from traumatic brain injury caused by multiple blunt force trauma; he had a history of alcohol abuse and multiple acts of violence. Individual GX-2024-017-B, a female aged 25-30, died from mechanical asphyxiation combined with a fall from a height; she suffered post-mortem sharp force trauma and had endemic fluorosis. These skeletal pathological characteristics and injury mechanisms will provide crucial physical evidence for the case investigation.
As the samples were sent to the DNA lab, the lights in the autopsy room remained bright. In the microscopic world of bones, the arrangement of every trabecular bone and the direction of every fracture line carry the last encounter of the deceased. Zhang Lin and his team are dedicated to deciphering these silent codes and letting the bones tell the truth.
On the second day, Li Ming convened a case analysis meeting.
As the projection screen in the conference room lit up, the first rain of autumn was falling outside the window. Li Ming stood in front of the whiteboard, circling the location of the construction site on the map with a red pen. The strokes of the pen seemed to burn the truth out of this land that hid secrets. "Today's analysis meeting will focus on the two skeletons." He looked around at the attendees. "Xiao Yang and Zhang Lin will first report on the investigation and identification results. Xiao Wang will supplement the interview findings. We must determine the identities of the deceased as soon as possible."
Xiao Yang stood up first and pulled up a 3D scan model of the excavation pit site. On the computer screen, two curled-up skeletons reappeared in the virtual light and shadow, with scattered evidence around them flashing red: "The on-site investigation revealed that the two skeletons were stacked one on top of the other. The upper male skeleton held a button engraved with the letters 'J.C.' in its right hand, while the lower female skeleton clutched what appeared to be fabric fiber residue in its left hand." He switched to photos, and drag marks at the edge of the excavation pit were clearly visible in close-up shots. "Two different types of tire tracks were detected in the soil: one was a common truck tire, and the other was a larger SUV tire. The tread depth indicated that the vehicle was no more than three years old."
Zhang Lin opened the thick forensic report, and the X-ray images of the skeleton were spread out on the projector: "Based on the skeletal examination, the deceased was a male aged 35-40 years old, with a long history of alcohol consumption. He died from multiple blows to the right temporal bone caused by a round blunt object with a diameter of about 5cm. There are at least two fracture healing marks on the ribs at different times." He pulled up images of bone tissue under a microscope, and the degenerative features of the Haversian system were magnified on the screen. "Judging from the trabecular structure, the deceased may have engaged in heavy physical labor."
“The female victim was between 25 and 30 years old, and the cause of death is complex.” Zhang Lin switched to another set of images, where the linear fracture of the occipital bone contrasted sharply with the indentation on the maxilla. “There were concussion injuries from a fall, as well as signs of mechanical asphyxiation caused by suffocation. More importantly, her seventh rib on the right side was struck by a stainless steel knife after death, and analysis of the murder weapon residue showed it to be a common kitchen knife.” He held up an evidence bag containing metal fragments. “In addition, the female victim suffered from endemic fluorosis, a condition relatively common in high-fluoride areas of northern my country, which can serve as important evidence for identification.”
Xiao Wang then took over the conversation, slamming a stack of interview records on the table: "Our investigation around the construction site revealed that the land was abandoned industrial land before construction began. Nearby residents said they often heard strange noises last autumn and winter, but no one investigated due to its remote location. The only valuable clue came from a scavenger who witnessed a black SUV frequently coming and going last December. The driver was wearing a mask, and there was a long, tied-up object in the back of the vehicle." He pulled up a blurry surveillance screenshot; the license plate was obscured by mud, and only the letters "XK" could be vaguely seen. "We checked all black SUVs in the city with 'XK' in their license plates, totaling 237, but we couldn't narrow down the search further."
The meeting room fell silent, with only the sound of raindrops hitting the glass.