The crackdown on organized crime began with the arrest of the mother-in-law.

Chapter 1501 Clues from the On-Site Investigation

"Please rest assured, Captain Li, we will strictly follow the investigation specifications, conduct a meticulous investigation of the scene, and leave no stone unturned in order to successfully complete the investigation!" Xiao Yang said solemnly. He then turned to Xiao Sun and the other technical team members and gave them investigation instructions: "Everyone, please have a clear division of labor. Xiao Sun, you will work with me to be responsible for the extraction and analysis of trace evidence at the scene; Xiao Wang, you will be responsible for taking photos at the scene, from far to near, from the overall picture to the details, to comprehensively photograph the scene environment, the location of the body, and the distribution of trace evidence, ensuring that every photo is clear, complete, and can be used as evidence in the case; Xiao Li, you will be responsible for the investigation record, recording in detail the location, quantity, and characteristics of every investigation discovery, trace evidence extraction location, and every detail of the investigation process, without any omissions."

"Understood!" Xiao Sun, Xiao Wang, and Xiao Li responded in unison and immediately began their on-site investigation. As arranged by Xiao Yang, they first conducted a comprehensive investigation and took photos of the surrounding environment of the crime scene, following the principle of "from far to near," to ensure they had a grasp of the overall situation and to investigate any suspicious traces or physical evidence from a distance.

Xiao Wang picked up a professional forensic camera, adjusted the parameters, and first stood outside the cordon to take a panoramic photo of the scene. The photo clearly showed the area cordoned off, the location of the ditch, the state of the body in the ditch, and the surrounding environment, including sidewalks, bike lanes, guardrails, intersections, and convenience stores, ensuring a complete reconstruction of the crime scene's layout. He then slowly approached the scene, taking detailed photos from different angles and distances, focusing on the overall direction of the ditch, the condition of the guardrails, the condition of the sidewalks and bike lanes, and the locations of surrounding surveillance cameras. Each photo was labeled with the time and location of the shot for later review and analysis.

Meanwhile, Xiao Yang and Xiao Sun, following the cordon, gradually searched the area around the crime scene, looking for any suspicious traces or evidence, starting from the furnishings and moving closer. They first checked the area within 100 meters of the crime scene—the intersection to the east, the convenience store to the west, the entrance to the old residential building to the north, and the extended non-motorized vehicle lane to the south—carefully examining every surface, wall, and railing, leaving no corner unchecked.

"Captain Yang, look here. There's a small amount of mud on the sidewalk tiles. It looks fresh, but we're not sure if it's related to the case," Xiao Sun said, crouching down and pointing to a tile on the sidewalk. On that tile was an irregular mud stain, about the size of a palm. The mud was the same color as the mud in the ditch, and there were a few water stains on the surface, suggesting it was recently left, without any signs of rain or pedestrian damage.

Xiao Yang walked over quickly, squatted down, and carefully examined the mud mark. He gently touched the surface of the mud with his finger, feeling its moisture and hardness, and then said, "This mud is similar in composition to the mud in the ditch, but it cannot be determined whether it was left during the crime. It could also be that a sanitation worker accidentally spilled it while cleaning, or that a passerby accidentally stepped on the mud in the ditch and brought it to the sidewalk."

He paused, then continued, "Xiao Sun, use a cotton swab to collect a small amount of silt sample, put it in a sealed evidence bag, and mark it with the extraction location and time. We'll send it to the lab for component analysis and compare it with the silt in the ditch to confirm if they come from the same source. Also, carefully examine the ground around this silt mark to see if there are any footprints, fingerprints, or other suspicious traces, such as clothing fibers or hair."

"Understood, Captain Yang!" Xiao Sun quickly replied, taking out cotton swabs, a sealed evidence bag, and a marker from the investigation kit. He carefully used the cotton swabs to collect a small amount of silt sample, placed it in the evidence bag, sealed it, and labeled the bag: "Silt sample from the sidewalk bricks on the eastern section of Jianshe Road, collection location: approximately 15 meters from where the body was found, collection time: 7:15 a.m. that day." He then put the evidence bag back into the investigation kit, carefully examined the ground around the silt traces, shone a flashlight on it, and carefully checked every crevice, but found no footprints, fingerprints, or other suspicious traces.

Afterwards, Xiao Yang and Xiao Sun continued to approach the crime scene, searching the area within 50 meters of where the body was found. They focused their search on the guardrails on both sides of the ditch. The guardrails were made of concrete and covered with moss, making them extremely slippery. Xiao Yang shone a flashlight on every surface of the guardrails, carefully examining them for scratches, impact marks, fingerprints, hair, or other trace evidence. "Team Leader Yang, the guardrail surface is covered with moss and water stains, making it quite smooth. We haven't found any obvious scratches or impact marks, nor have we extracted any clear fingerprints," Xiao Sun reported to Xiao Yang while searching. "However, in one corner of the guardrail, we found a thin black hair, about 3 centimeters long, which looks like human hair. We extracted it for further examination."

Xiao Yang walked to the location Xiao Sun had indicated and carefully examined the black hair. The hair was stuck to the moss on the railing; it was extremely small and difficult to spot without close inspection. "Okay, extract this hair sample immediately and label it," Xiao Yang said. "Use tweezers to gently extract it, being careful not to damage the hair follicle, to ensure you can extract complete DNA information. We'll send it to the lab for testing to confirm whether it's human or animal hair. If it's human hair, we'll further analyze whether it was left by the deceased or a suspect."

Xiao Sun nodded, took out sterile tweezers and a sealed evidence bag from the investigation kit, carefully used the tweezers to grasp one end of the black hair, gently pulled it off the moss, placed it in the sealed evidence bag, labeled it, and put it back into the investigation kit. The two then continued to check the railings until they had checked both sides of the ditch, but found no other suspicious traces or evidence.

At this moment, Xiao Wang had finished taking photos and collecting evidence at the scene from a distance. He walked over to Xiao Yang and said, "Team Leader Yang, all the panoramic and close-up photos of the scene from a distance have been taken. A total of 46 photos have been taken, each marked with the time and location of the shot. They are clear and complete, and can restore the overall environment and local details of the scene." Xiao Yang nodded and said, "Okay, thank you for your hard work. Next, cooperate with us to conduct a close-up investigation of the scene, focusing on taking photos of the location of the body, the details of the body's surface, and the process and location of our extraction of trace evidence."