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

The ground was covered with tire tracks, messy and disorganized, making it difficult to discern any useful clues. Yang Sen, squatting beside the sewage outlet of the compression station, used tweezers to clear away the accumulated silt, when suddenly his eyes lit up. "Look at this!"
A small fragment of black plastic was held in the tweezers, with obvious cut marks on the edges. Its material matched perfectly with the black plastic bag that had wrapped the body. The fragment had a few dark red stains and a few brown fibers on it. Yang Sen placed the fragment into an evidence bag. The stains looked like dried blood, but after soaking in the sewage outlet for so long, it was uncertain whether they would be detectable. The fibers were coarse, like some kind of fabric; they might be from the deceased's clothing or the suspect's clothing.

Yang Lin leaned closer for a closer look. The cut surfaces of the plastic fragments were very clean, unlike those broken by a garbage truck. It seemed more like the suspect had accidentally torn the plastic bag while wrapping the body. "Let's look along the sewage outlet and see if there are any other fragments." The two walked about 20 meters along the ditch of the sewage outlet and found two more similar black plastic fragments. One of them had a small amount of cement residue on it, consistent with the cement residue found on the plastic bag containing the body.

It seems the suspect did indeed stay in this area, and these plastic fragments were likely left behind when he disposed of plastic bags. Yang Lin marked the location of the fragments in his notebook. However, the tire tracks here were too messy to distinguish which vehicle belonged to the suspect. The only certainty was that the suspect might have been familiar with the operating hours of the compression station and deliberately chose to dispose of the body when no one was around.

The two then turned to the corner of the north wall. The wall was about 2.5 meters high, its surface mottled and covered in graffiti. At its base were piles of discarded planks and old furniture, making it the most secluded area of ​​the entire landfill. Yang Sen used a probe to move aside a pile of discarded mattresses, when suddenly a soft clinking sound came from behind him. The probe had struck a metal object.

The two carefully moved the mattress, revealing a silver metal button on the floor. It was about 1.5 centimeters in diameter, with signs of wear and faded patterns engraved along the edges. The button was made of gold-plated brass and looked quite old, unlike something from new clothing. Yang Lin placed the button into an evidence bag. Next to the button, in the soil, they found half a footprint—a size 43 men's sneaker print—matching the shoe print previously found to the east of the body!
The footprints were only the first half, with the toe lines clearly visible. Small amounts of red paint particles were mixed in with the mud, matching the composition of the red paint spots on the plastic bag containing the body. This indicates the suspect did indeed walk along the base of the wall and likely stopped there. Yang Sen measured the depth of the footprints with a ruler. The footprints were embedded about 1 centimeter in the mud. Considering the moisture level of the mud, the footprints were estimated to have been left within 24-48 hours, which largely matches our estimate of when the body was disposed of.

Continuing the search along the base of the wall, Yang Lin found a cigarette butt near a broken drain. The cigarette butt was a Hongtashan brand, with obvious teeth marks on the filter and a small amount of gray dust on its surface—dust characteristic of landfills. There should be the suspect's saliva on the cigarette butt; although it had been exposed for so long, the forensic team might be able to extract DNA. Yang Lin placed the cigarette butt into a special DNA collection bag. Furthermore, the degree of burning indicated that the suspect had only smoked less than a third of it before discarding it, possibly due to nervousness or hearing some noise and hastily leaving.

Yang Sen then found a thin, long metal wire, bent into a hook shape, inside the drain hole. The wire was made of iron, with a rusty surface, and one end was sharpened. He picked up the wire with tweezers. It looked like it had been deliberately sharpened; it might have been a tool the suspect used to pry open the gate lock, or perhaps used to hook garbage to cover a body. However, the drain hole was very small, so it was strange that the wire had ended up there.

The two continued to expand their investigation, making a new discovery near the conveyor belt in the abandoned sorting area. The conveyor belt had long since stopped operating, its surface covered with a thick layer of dust. Within the dust, Yang Sen found several shallow scratches, all pointing in the same direction, as if caused by being dragged by some hard object. Black plastic residue remained at the edges of the scratches, matching the material of the plastic bag that had wrapped the body. Yang Sen shone a powerful forensic light on the scratches. Furthermore, the length of the scratches was similar to the length of the body, suggesting that the suspect might have briefly stopped there, placed the body on the conveyor belt, and then moved it to the disposal site.

In a storage box beneath the conveyor belt, Yang Lin also found a crumpled tissue with a small amount of brown stain and a few short hairs on it. The short hairs were black, about 5 centimeters long, and soft, likely left by the deceased or suspect. Yang Lin unfolded the tissue and carefully placed it into an evidence bag. The stain was similar in color to the dark red stain he had previously found on the plastic fragments; they needed to be tested together to see if they came from the same source.

Before they knew it, the two had been investigating for nearly three hours, and the evidence bags they had collected were nearly half full in their investigation kits. Yang Sen leaned against the wall, took off his gas mask to catch his breath, and his voice was tinged with exhaustion. Although they had found plastic fragments, buttons, cigarette butts, there were still no clues that could directly point to the suspect's identity, and the identity of the deceased remained unknown. "Do you think that metal button and chain might have been accessories the deceased carried? Like a belt buckle or parts from a wallet?"
Yang Lin also took off his mask and rubbed his aching cheeks. It's possible, but there were no markings on the buttons, and the chain was only a short section; it would be difficult to identify the deceased based on these alone. Furthermore, whether DNA could be extracted from the cigarette butts and tissues was another question; the landfill environment was too complex, with too many pollutants, which could easily damage the DNA samples.

He paused, flipping through the notes in his notebook. Several points were certain. First, the suspect was 175-180 cm tall, wore size 43 sneakers, was familiar with the landfill environment, and knew the western surveillance cameras were broken and the operating hours of the compression station. Second, the suspect carried cutting tools, possibly a knife or scissors and wire, indicating a degree of counter-surveillance awareness; he deliberately removed the victim's belongings and chose a concealed route to dispose of the body. Third, the suspect likely drove a white van; there were items covered with tarpaulin in the back seat, the left headlight was broken, and the engine was making unusual noises. While these characteristics were clear, there were too many white vans in the surrounding towns, and without further clues, the investigation would be extremely difficult.

Yang Sen nodded and added, "Also, the suspect was likely wearing dark clothing when he disposed of the body, because the brown fibers and black plastic fragments we found are not easily spotted in a landfill." (End of Chapter)