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

“Especially the shoes and clothes.” Lu Chuan glanced at his watch. It was 7:15 a.m., two hours after the body was discovered. The sun was slowly rising over the roof of the farm, illuminating everything clearly, including the traces hidden in the pig manure and silt.

Lu Chuan's shoes clicked crisply on the frozen ground of the farm. As he turned, bits of pig manure from his scarf fell onto the map showing the "further investigation area." "Extend 50 meters east and west, and 30 meters north and south, from the third pigpen as the center," he drew a rectangle on the map. "Focus on checking the joints of the fences, the back wall of the feed warehouse, and that row of abandoned disinfection pools. Don't overlook any abnormal traces." The cold wind swept past, carrying the squeals of the pigs. Yang Lin was stuffing the batteries of the multi-band light source into an insulated bag to prevent the low temperature from affecting the spectral stability.

Yang Sen had already set up a survey light on the tin roof of the feed warehouse. The beam of light pierced through the frosted glass windows, casting dappled shadows among the piles of burlap sacks. "Brother Lin, look at the dust on the ground," he said, pressing an electrostatic precipitator close to the ground. Several silvery-white metal shavings immediately stuck to the black plastic sheet. "The X-ray fluorescence spectrometer measured it. It contains 37% lead and 63% zinc. It's a component of solder. This warehouse is usually only used for storing feed; there shouldn't be this stuff here."

Yang Lin was kneeling on the edge of the cement platform in the pigsty, the blue-violet light from a multi-band light source sweeping across the cracks in the corner of the wall. "The fiber density of the drag marks suddenly increases at 1.2 meters," he said, picking up a strand of dark blue polyester fiber with tweezers and placing it on a glass slide. "The warp and weft density is 120 x 80 threads per inch, consistent with the density of the deceased's work clothes, but with a higher twist, as if it had been torn violently." He had the technicians take samples deep into the crack, and a plaster model showed a fragmented fingerprint there, the lines of which matched the right thumb of an adult male.

“There are fresh climbing marks on the back wall of the warehouse,” Yang Sen’s shout came from the east. He was measuring the height of the wall with a laser rangefinder. “2.3 meters. 2 x 3 centimeters of cement on the wall has been rubbed off, and there is a size 44 shoe print on the exposed red brick. The forefoot pressure area is on the outside, which is consistent with the force exertion characteristics of a left-handed climber.” In the withered grass at the base of the wall, there was a flattened cigarette box. “Hongtashan cigarettes. The filter of the cigarette butt has a faint minty flavor. DNA testing needs to be done when I get back, but the degree of burning of the tobacco indicates that it was smoked around 10 pm last night.”

Yang Lin's attention was focused on the abandoned disinfection pool. A thin layer of ice covered the bottom, and beneath it lay a blurry shadow. "Bring the pump," he said, using an ice pick to break through the ice. "It looks like a steel pipe, about 80 centimeters long." The pump roared, pumping water into the drain. The exposed steel pipe was stained with dark red marks, which tested positive with benzidine reagent—likely blood. One end of the pipe showed obvious signs of impact, its edges curled, matching the dents on the fence latches.

“The lock cylinder in the feed warehouse is a ‘Meilibao’ Class C lock,” Yang Sen said, squatting in front of the padlock. Under his magnifying glass, the pins showed fresh scratches from being pried open. “But it wasn’t forced open; it’s like a master key was used. The brass powder in the lock cylinder is the same as the one in the drawer lock of the farm’s office, which means the key was probably duplicated by an insider.” He suddenly pointed to the scale in the corner of the warehouse. “The display screen of this scale is still lit up. The last weighing record was at 9:47 pm last night, 238 kilograms, 50 kilograms more than the usual feed weight.”

Yang Lin made a new discovery in the mud beside the disinfection pool. "This series of footprints has alternating limping characteristics," he said, using a ruler to mark the imprint of a size 44 safety shoe. "The pressure surface of the left heel is 30% smaller than that of the right foot, as if there was an old injury in the left leg." The footprints extended to the asphalt road outside the fence and disappeared into the roadside ditch. "The sand content of the mud at the edge of the shoe print suddenly increases, indicating that a change of transportation started from here. There are tire marks on the wall of the ditch, 18 centimeters wide, which matches the width of a motorcycle tire."

“Brother Lin, look at this brown shoelace,” Yang Sen ran over, holding an evidence bag. The end of the shoelace inside the bag had burn marks. “It was found in the seams of a burlap sack in the feed warehouse. The fiber composition is exactly the same as the one in the fence planks, but the heat distortion of the burn marks is from left to right, like it was lit with a lighter.” He suddenly remembered something. “The deceased’s work shoes had black shoelaces. This one is clearly not his. It’s very likely that the murderer dropped it.”

By noon, the sunlight had finally dispelled some of the chill. As Yang Lin sorted and packed all the samples, Yang Sen was summarizing the anomalies: "Solder shavings, climbing marks, bloodstained steel pipes, limping footprints, burning shoelaces... these clues can be connected, but a crucial link is missing." He pulled up a satellite image of the farm. "Look," he said, "there's a hidden route, 15 meters in a straight line, from the back wall of the warehouse to the third pigpen, perfectly avoiding all blind spots in the surveillance. The killer was extremely familiar with the terrain here."

Yang Lin's gaze fell on the scale, the display still showing 238 kilograms. "Normal feed bags weigh 50 kilograms each, so 238 kilograms is more than four bags," he suddenly frowned, "but the sacks in the warehouse are all full, there's no shortage, so what's this extra 50 kilograms?" He asked the technicians to open the nearest sack, and found a few grayish-white pig hairs mixed in with the feed—the DNA matched that of the pigs from the third brood, but the hair follicles had fallen out, as if they had been deliberately mixed in.

“There’s a 30-centimeter gap in the metal mesh of the fence,” Yang Sen shouted from the west. He used a spectrometer to examine the edge of the gap. “The oxide layer broke within 12 hours. The fibers on it are made of polypropylene, which is commonly used in woven bags and has the same composition as the feed bags commonly used in pig collection trucks.” In the mud outside the gap, there was a patch of crushed clover. The dew on the leaves had dried, but the degree of cell rupture indicated that it was trampled around 2 a.m.

When the investigation expanded to the area near the transformer at the farm, Yang Lin discovered a suspicious tire track. "These are the steering wheel tracks of a small truck," he said, using plaster to create a mold. "The tread pattern is the horizontal stripe of the 'Linglong' brand, which matches what Chen Jianfeng described as a pig-collecting truck, but there's a sharp turn mark about 5 meters from the fence, as if the driver suddenly changed his mind." Soil samples from the tire track tested positive for trace amounts of diesel fuel, consistent with the composition of No. 0 diesel fuel at a nearby gas station.

By 3 PM, when all the samples were packed and transported away, Yang Lin and Yang Sen's notebooks were filled with 37 clues. The infrared spectrum of the dark blue fiber, the preliminary blood type test results from the blood-stained steel tube, the three-dimensional model of the limping footprint, and even the burned brown shoelace—all were labeled and awaiting laboratory analysis. (End of Chapter)