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

After completing the exterior examination of the taxi, the two began to focus their investigation on the interior. The deceased in the driver's seat was leaning slightly forward, with his head tilted to the right and his hands resting naturally on the steering wheel. There was an irregular dark stain on his chest, approximately 20cm x 15cm in size. His clothing was torn, with irregular, ripped edges. Yang Lin first recorded the deceased's position and condition, measuring his height and sitting position with a tape measure. He then carefully laid the body flat to avoid disturbing any remaining traces.

"The area around the driver's seat is a key area for investigation. Pay attention to collecting fingerprints and traces from the steering wheel, gearshift, handbrake, and inside door handles," Yang Lin said. He used fluorescent powder to highlight the steering wheel, revealing multiple fingerprints, most of which belonged to the deceased. However, on the left edge of the steering wheel, he found an unfamiliar fingerprint with clear lines. He immediately extracted it with fingerprint extraction tape and marked it as "Fingerprint Sample No. 5 from the Scene." Multiple fingerprints were also extracted from the gearshift and handbrake, and preliminary comparison showed that they matched the characteristics of the unfamiliar fingerprint on the steering wheel.

Yang Sen carefully examined the ground and seat around the driver's seat with an investigation light: "The driver's seat is made of black leather, with a small amount of bloodstains on the surface, the same color as the dark stains on the deceased's chest; there is a fallen cigarette butt under the seat, brand 'Chunghwa', not completely burned, with obvious saliva residue on the cigarette butt." He carefully picked up the cigarette butt with tweezers and put it into the evidence bag, labeling it "Sample No. 1 left at the scene". At the same time, he used a fiber extractor to extract fiber samples and bloodstain samples from the surface of the seat, labeling them "Fiber Sample No. 2 at the scene" and "Bloodstain Sample No. 2 at the scene", respectively.

In the passenger seat of the taxi, the two men found an open glove compartment containing a taxi operating license, an ID card, some loose change, and a smartphone. Yang Lin picked up the operating license and ID card and examined them carefully: "The deceased's identity confirmed: Zhang Tiancheng, male, 45 years old, registered residence at Room 501, Unit 2, Building 3, Xingfu Community, Chengbei District, holding a valid taxi operating license." He placed the operating license and ID card into an evidence bag as evidence of the identity verification.

Yang Sen inspected the smartphone: "The phone is a Huawei brand, the screen is intact, it's locked, and the battery has 30% remaining. There are a few fingerprints on the surface of the phone, which, after preliminary comparison, are the deceased's fingerprints." He tried to unlock the phone, but because it was password protected, he couldn't open it and had to seal it away, preparing to take it back to the technical department for data recovery and fingerprint extraction. On the floor of the passenger seat, the two also found a crumpled taxi receipt, dated 11:30 pm the previous night, with the destination near the intersection of Binhe West Road and Chaoyang North Road, the amount being 25 yuan, and the payment method being cash.

“This receipt is very important. It shows that the deceased picked up a passenger in this area at 11:30 pm the night before, and it’s very likely that he was the last passenger to commit the crime,” Yang Lin said. He carefully unfolded the receipt, put it into the evidence bag, and labeled it “Sample No. 2 left at the scene.” Subsequently, the two examined the back seat of the taxi. The surface of the back seat was clean, and no bloodstains, hair, or other suspicious traces were found. However, in the gap of the right back seat, they extracted a few black hairs and a small amount of white synthetic fibers, which were labeled “Hair Sample No. 3 at the scene” and “Fiber Sample No. 3 at the scene”, respectively.

On the taxi's dashboard, the two men found a dashcam, which was switched off. Yang Sen removed the dashcam's memory card, marking it "Sample No. 4 Left at the Scene," intending to take it back to the technical department to extract the video data. In the storage compartment below the dashboard, there was an unopened pack of "Zhongnanhai" cigarettes, a lighter, and several blank taxi receipts; no unusual items were found.

To confirm whether the scene was the primary crime scene, Yang Lin and Yang Sen conducted a detailed examination of the bloodstains inside the taxi: "The bloodstains on the deceased's chest were in a soaking pattern, and the bloodstains on the seat corresponded to those on the deceased's chest. No splattered bloodstains were found, indicating that the deceased was likely attacked while seated and did not struggle violently after the attack." The two used multi-band light sources to illuminate various corners inside the taxi and found no other bloodstains on the driver's seat back, the inside of the doors, and other areas, further confirming their hypothesis that the scene was likely the primary crime scene.

After examining the interior of the taxi, the two began to expand their search area, conducting a comprehensive investigation of the road surface, sidewalk, and green belt within a 50-meter radius of the taxi. About 3 meters to the left of the taxi, on the sidewalk, Yang Sen discovered a clear footprint: "The footprint is male, shoe size 43, athletic casual shoe, with a wavy tread pattern. The forefoot tread shows relatively little wear, while the heel shows significant wear. It is estimated that the owner of the footprint is between 30 and 40 years old, 178-183 cm tall, and weighs 75-80 kg." He used plaster powder to infuse the footprint, extracting this sample, which he labeled "Footprint Sample No. 1 at the Scene."

About 5 meters from the taxi, on the edge of the green belt, Yang Lin found several dark red drops of blood, about 1.2 meters high, roughly matching the height of the deceased's chest. "These drops of blood are suspicious. They may have been bloodstains on the suspect's body that dripped down when he left after committing the crime." He used a cotton swab to collect a blood sample, marking it "Bloodstain Sample No. 3 at the scene." At the same time, he shone an investigation light around the area but found no other bloodstains or suspicious traces.

In addition, the two also collected several black hairs and a small amount of white synthetic fibers from the road surface around the taxi. These fibers were similar in characteristics to those found in the crevices of the taxi's back seats and were labeled "Hair Sample No. 4 at the Scene" and "Fiber Sample No. 4 at the Scene," respectively. Inside the green belt, they also found a broken plastic bottle and a crumpled tissue, preliminarily determined to have been left by a passerby. These have not yet been collected and will require further investigation based on other clues.

现场勘查工作持续了近6个小时，直到中午12时才结束。杨林和杨森共提取到各类痕迹物证32件，其中包括指纹样本5份、血迹样本3份、毛发样本4份、纤维样本4份、足迹样本1枚、微量物质样本1份、遗留物样本4件（烟蒂、发票、手机、车载记录仪内存卡）及车载记录仪1台。所有物证均已封装标记，准备带回技术科进行进一步检验。(本章完)