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

"The perimeter investigation is complete. We found a suspected footprint and extracted a model. No other obvious abnormalities were found in the area," Yang Sen reported to Yang Lin, carefully putting away the footprint evidence bag. Yang Lin nodded and said, "Okay, now let's go inside the factory for investigation. Be careful to keep the scene in its original state and do not touch any items. We will conduct static observation first, and then proceed with dynamic extraction."

The two pushed open the crooked factory door, and a strong stench assaulted their senses, a mixture of blood, decay, and dust that was nauseating. Yang Sen frowned instinctively, took out his air freshener, and sprayed it a few times at the doorway, slightly alleviating the odor. The factory was dimly lit, with only a small amount of light filtering through the broken windows. Yang Lin immediately turned on his survey light, the bright beam instantly illuminating the entire interior.

The factory's interior was spacious, approximately 200 square meters, with a cement floor covered in a thick layer of dust due to years of disuse, and some areas showing mold due to dampness. The factory contained a large amount of abandoned logistics equipment, including dilapidated forklifts, conveyor belts, shelves, and packaging machinery, haphazardly scattered throughout, creating several cramped spaces. The body was located at the innermost part of the factory, near the north wall, lying supine on the floor, covered with a worn blue coat. There were obvious bloodstains around the body, dried and blackened, spreading in irregular patterns.

Yang Lin and Yang Sen did not immediately approach the body. Instead, they stood at the factory entrance, using the light of their investigation lamps to conduct a comprehensive static observation of the factory interior. Simultaneously, they used their cameras to photograph the layout, equipment placement, the location of the body, and the surrounding environment from all angles. "From the overall environment, there are few signs of human activity inside the factory. The dust is evenly distributed, and apart from the area around the body and the entrance, no obvious signs of trampling were found elsewhere," Yang Lin said as he observed. "The perpetrator most likely entered this factory intentionally and may have done a simple cleanup afterward."

Yang Sen focused on observing the layout of the passageways and equipment inside the factory: "The equipment inside the factory is cluttered, and the passageways are narrow. After entering the factory, the murderer should have walked along the west passageway to the innermost part, committed the crime, and then returned along the same route. We are focusing our investigation on the west passageway and the area around the body to see if we can find any more clues."

After the static observation, the two began a dynamic investigation along the west side of the factory, proceeding from the outside in. The passageway was about 1.5 meters wide, with abandoned shelves and forklifts piled up on both sides. The shelves were covered with a thick layer of dust, and some were tilted due to years of disrepair. Yang Lin used a brush and tweezers to carefully clean the dust off the shelves, while also checking for fingerprints, hair, or fiber residue. Yang Sen, on the other hand, used a footprint lamp to examine the footprints on the ground, comparing them with the characteristics of footprints extracted from the surrounding area.

“Yang Sen, look at this dust; it shows signs of being disturbed,” Yang Lin said, stopping beside a shelf and pointing to its side. There was an irregular scratch on the dusty side of the shelf, its edges clearly defined, surrounded by loose dust, indicating it had been recently touched. Yang Lin immediately took a picture of the scratch, then used an electrostatic precipitator to collect any remaining fingerprints or fibers. “The scratch is about five centimeters wide and shallow; it’s most likely left by the perpetrator accidentally brushing against the shelf with their body or belongings.”

Upon hearing the news, Yang Sen rushed over and shone a footprint light on the ground around the scratches. He discovered a blurry footprint on the ground, similar in characteristics to the footprints previously extracted from the weeds outside the factory. It was also a men's leather shoe print with a checkered sole pattern, but the edges were somewhat blurred due to the thick layer of dust on the ground. "This footprint should be from the same person as the one outside, further indicating that the murderer entered the factory through this passage," Yang Sen said. He then followed the footprint extraction procedure, using plaster powder to fix and extract the footprint.

The two continued their investigation along the passage. About ten meters from the body, Yang Sen discovered another clear footprint on the ground. This footprint was more complete than the previous one, with the sole pattern and wear clearly visible. "This footprint is well-preserved and can provide us with more characteristic information," Yang Sen said excitedly, carefully extracting it. Yang Lin, meanwhile, found several thin fibers on the ground next to the footprint. The fibers were black, soft, and about two centimeters long. He immediately used tweezers to gently pick up the fibers, placed them in a transparent evidence bag, and marked it.

“These fibers look like wool, possibly from the killer’s clothing or items used to wrap the body,” Yang Lin said, carefully examining the fibers in the evidence bag. “We’ll have the technical department analyze the composition when we get back to see if we can determine the exact source of the fibers.”

As the two approached the body, the stench in the air grew increasingly intense. On the ground around the body, dried blood formed an irregular bloodstain, roughly one square meter in area. There were clear wiping marks at the edges of the bloodstain, suggesting that the perpetrator had wiped the ground with clothing or other items after the crime, but the wiping was incomplete, leaving a large amount of blood behind. Yang Lin and Yang Sen conducted a meticulous examination of the bloodstain area. Yang Lin used a cotton swab to collect a small blood sample, placing it in a bloodstain preservation tube, while simultaneously photographing and recording the shape and distribution of the bloodstain. Yang Sen, on the other hand, used a footprint lamp to illuminate the area around the bloodstain, searching for any footprints or other traces left by the perpetrator.

"The bloodstains are irregular in shape and have splatter marks at the edges, indicating that the blood flowed out in a spray when the victim was killed, which is consistent with the characteristics of massive bleeding caused by a sharp instrument cutting the neck," Yang Lin analyzed. "The wiping marks are rather messy, indicating that the murderer may have been in a panic after committing the crime and did not clean up the scene in a haphazard manner."

Yang Sen discovered another footprint on the ground near the edge of the bloodstain. This footprint was partially covered by blood, but the tread pattern of the shoe sole was still clearly visible, perfectly matching the previously extracted footprint, further confirming the killer's footprint characteristics. "After committing the crime, the killer must have been cleaning up the bloodstain while standing at the edge, leaving this footprint," Yang Sen said, while simultaneously taking a sample of the footprint.

By this time, the forensic team had arrived at the body and begun a preliminary examination. Yang Lin and Yang Sen temporarily avoided the area containing the body and instead examined the north wall and surrounding equipment inside the factory building. The north wall was mottled with multiple cracks, and abandoned packaging machinery was piled up in the corner, its surfaces covered with a thick layer of dust and mold. (End of Chapter)