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

"Did you hear anything when you patrolled this area last night?" Wang Shuai pressed, his gaze falling on the patrol log on the wall of the duty room, where Lao Liu had signed at 1:15 a.m. "It was windy then," Lao Liu recalled, clicking his tongue. "I think I heard a muffled 'bang,' and I thought someone slammed a car door too hard. Now that I think about it..." He suddenly lowered his voice, "Lao Zhao's company has been owing a lot of money lately. Last week, someone even blocked him in the garage, demanding to take his car to pay off the debt."

In the garage, Yang Lin used tweezers to pick up a fiber from the corner of the deceased's clothing: "Dark blue, double-woven, not pajamas material." He looked up at the trunk of the Passat, where Yang Sen was using a crowbar to pry open a displaced mat. The dark red debris exposed beneath the mat gleamed oily under the light. "The trunk lock shows signs of tampering," Yang Sen's voice resonated metallically, "and there's some silvery-white powder stuck in the lock cylinder, like paint."

Lu Chuan's gaze swept over the surveillance camera on the garage roof: "Wang Shuai, contact the property management to retrieve the surveillance footage from the past three days, focusing on the period between midnight and 2 a.m., especially the entry and exit records of the red Civic and the white van." He kicked away an empty wine bottle at his feet; the fingerprints on the bottle did not match the deceased's. "Investigate Zhao Jianguo's social connections, especially his debt disputes and recent contacts."

Yang Lin suddenly squatted down beside the Passat's left rear wheel, picking up a strand of silvery-white fiber with tweezers: "It matches the ligature marks on the deceased's ankle." He looked in the direction the fiber extended, and saw a torn piece of paper stuck in a crack in the concrete, with the words "Loan Contract" faintly visible. Yang Sen was measuring the distance from the steering wheel to the brake pedal: "28 centimeters, consistent with the driving habits of a male around 175 centimeters tall, but the seat position is 5 centimeters forward than usual."

As the technicians filled the shoe print with plaster, Yang Lin lifted the hem of the deceased's pajamas, revealing obvious drag marks and creases at the lower back. "There were light-colored drag marks on the ground from the vehicle to the body, 1.7 meters long," he said, shining a UV light on them, revealing pale green fluorescence at the edges. "The oil stains on them were consistent with the composition of the engine oil in the Passat's engine compartment."

Wang Shuai's notebook was already four pages full, while Lao Liu was still listing Lao Zhao's grievances: "His ex-wife came to make trouble last week, saying she would go to the company to cause trouble if he didn't pay child support; and there's Lao Wang downstairs, who argued with Lao Zhao until the property management called the police because his electric scooter was flooded by a leak in the garage..." He suddenly pointed out the window, "That red Civic! It's parked downstairs in Building 3, the owner's name is Li Wei, he's a small contractor for a decoration company."

Looking at the seventeen suspicious points marked by Yang Lin, Lu Chuan suddenly pointed to the Passat's exhaust pipe: "Check the vehicle's recent driving trajectory, especially last night's GPS records." He bent down and picked up the slippers next to the deceased's feet. The tread pattern on the soles matched the marks on the floor mat at the garage entrance perfectly. "He must have walked here from the elevator entrance. He might have encountered something along the way."

The motion-activated lights suddenly went out, and Yang Lin's voice came from the darkness: "Sample taken from the debris under the trunk mat; suspected bloodstains." When the flashlight beam came back on, it illuminated Zhao Jianguo's wide-open eyes, as if he were still staring at a figure emerging from the shadows. Lu Chuan knew that on this seemingly calm concrete ground, every fiber, every mark, was a signpost pointing to the truth.

Lu Chuan's leather shoes tapped crisply on the cement floor. He stood in the center of the garage, his gaze sweeping over the outline of the body circled in chalk: "Yang Lin, conduct a radial investigation from the center of the body outwards, dividing it into 50-centimeter sections. Focus on extracting biological samples and trace evidence. Yang Sen, be in charge of the vehicle's 3D scanning and tire tread comparison. Don't overlook any signs of wiping." His fingertip pointed to the Passat's trunk, "Especially the silvery-white powder inside the lock cylinder. Use sterile cotton swabs to collect samples to avoid cross-contamination."

Yang Lin had already set up a multi-band light source; under the blue beam, the concrete ground around the body fluoresced a pale green. "Marker number 12," his voice came through his mask, "is a suspected bloodstain 30 centimeters from the right shoulder of the body, in a droplet shape, 0.8 centimeters in diameter. Preliminary testing with Sudan Black staining is positive." He aligned the scale bar with the edge of the blood droplet and took three photos each from a downward angle and a 45-degree angle. "During extraction, use a cropping method to preserve a 2-centimeter radius of matrix around the blood droplet to prevent DNA degradation."

Yang Sen was using magnetic powder to treat the Passat's door handle: "There's a whorl-shaped fingerprint on the driver's side door handle, with the central pattern spiraling counterclockwise and the ridges spaced 0.3 millimeters apart, but the edges are blurry, possibly due to a humid environment." He sprinkled on gray magnetic powder and gently swept it with a soft brush. "There are 5 feature points where the ridges break, which match the characteristics of an adult fingerprint. It needs to be developed with 502 glue to extract the complete shape." The powder on the passenger side door handle showed a different result—only messy scratches, as if it had been repeatedly rubbed with rough cloth.

“The silvery-white fibers from the ligature marks on the corpse’s ankle,” Yang Lin picked up with tweezers and placed them on a glass slide, examining them under a portable microscope. “They are 12 micrometers in diameter, with a birefringence of 1.56, exhibiting characteristics of polyester, but with obvious signs of wear on the surface, suggesting they may have been washed multiple times.” He divided the fibers into three portions and placed them into evidence bags labeled “Comparison Sample A,” “Spectroscopic Analysis,” and “DNA Extraction,” respectively. “They need to be sent to the laboratory for infrared spectroscopy and elemental analysis to determine their specific origin.”

Yang Sen moved his laser rangefinder inside the Passat's trunk: "The trunk mat shifted 17 centimeters, with 2.3-centimeter wrinkles along the edge, consistent with dragging characteristics." He shone a UV lamp on the mat, revealing several light brown marks under the dark purple light. "Suspected occult blood; tested strongly positive with tetramethylbenzidine reagent, but the morphology is incomplete, requiring a lab test for bloodstain pre-testing and species identification." When the silvery-white powder inside the lock cylinder was sampled, he suddenly frowned. "This powder contains tiny glass shards, with a refractive index of 1.52, like ordinary window glass."

The drainage ditch in the northwest corner of the garage became the focus of the investigation. Yang Lin knelt by the ditch and used a straw to siphon away the murky water: "There is a fragmented footprint on the ditch wall, with the forefoot part well preserved," he measured the data, "Stride length 78 centimeters, stride width 15 centimeters, foot angle 12 degrees, consistent with male walking characteristics." The pressure area of ​​the forefoot of the footprint is diamond-shaped, with a 0.2-centimeter outward turn at the edge, "Compared with the size 42 shoe print next to the body, the pattern type is consistent, but the wear is lighter, possibly left by the same pair of shoes at different times."

Yang Sen was applying a smoke-on treatment to the Passat's steering wheel. Super glue vapor condensed inside the glass cover, gradually revealing the previously blurry wiping marks: "The clean area at the three o'clock position is actually an overlapping fingerprint," (End of Chapter)