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

At 9:00 AM, Xiao Zhang and his teammate Xiao Li arrived at the Little Rabbit Dental Clinic. Located in a bustling area on the eastern side of the northern suburbs, surrounded by several large residential areas, the clinic's interior was clean and bright, a stark contrast to the small private clinics they had previously investigated. Upon learning their identities, the receptionist immediately led them to the clinic manager's office. The manager, a woman in her fifties surnamed Liu, had worked in the dental industry for many years. Upon learning the police's purpose, she did not hesitate and immediately expressed her full cooperation.

"Dr. Liu, we need to investigate male patients your clinic has treated in the past three months who meet the following characteristics: age 38-42, height approximately 175 cm, medium build, and who have previously undergone a fine resin filling for caries in their right upper second molar." As Xiao Zhang spoke, he handed Dr. Liu a close-up photo and detailed parameters of the deceased's tooth filling.

Dr. Liu took the photos and parameters, put on her reading glasses, and examined them carefully. Her brow furrowed slightly. "This filling technique is indeed quite delicate. Only two doctors in our clinic can perform this kind of high-precision filling surgery. The medical records from three months ago... Our clinic keeps both electronic and paper records. I'll have the nurse retrieve the relevant records right away." After saying that, she immediately dialed the nurses' station and requested to retrieve the medical records of all male patients who had undergone resin filling surgery on their maxillary second molars within the past three months.

While waiting for their medical records, Dr. Liu explained to Xiao Zhang and Xiao Li, "We are a chain institution with strict regulations for medical record management. All patients have their detailed information registered upon arrival, including their ID number, contact information, and address. Unless it's an emergency or a special case, anonymous visits are not allowed." This reassured Xiao Zhang and Xiao Li. Their biggest concern was the lack of patient information. If this clinic's medical records were standardized, the chances of finding clues would greatly increase.

A dozen minutes later, the nurse delivered the organized medical records to the office—seven electronic medical records and their corresponding paper copies. Dr. Liu reviewed them one by one, while Xiao Zhang and Xiao Li stared intently at the electronic records on the screen. "Age doesn't match, this one's only 28; this is a mandibular molar filling, the position is wrong; this is an amalgam filling, the material is different..." Dr. Liu muttered to himself as he sorted through the records. Xiao Zhang's heart raced, his eyes glued to the patient information and treatment notes in each record.

Just then, Dr. Liu's finger stopped on an electronic medical record, and her brow relaxed slightly. "Look at this one. The patient's name is Zheng Kaibin, age 40, height 176 cm, medium build. The consultation date was three months ago, October 12th. The treatment was a resin filling for the caries in his right upper second molar. Moreover, the attending physician is a key technical staff member in our clinic, specializing in delicate filling procedures." She clicked on the treatment details in the medical record, which contained detailed records of the filling's dimensions, resin material type, and even close-up photos of the surgical procedure.

Xiao Zhang quickly stepped forward, his gaze falling on the surgical photograph in the medical record. The shape and location of the filling shown in the photograph were almost identical to the characteristics of the filling in the deceased's tooth provided by Zhang Kai. "Dr. Liu, could you let us see the detailed information in this medical record? Including the patient's address, contact information, ID number, etc." Xiao Zhang's voice was filled with barely suppressed excitement.

Without hesitation, Dr. Liu handed the paper medical record to Xiao Zhang: "Look, this is a photocopy of the patient's ID card. It has complete identification information. The address is Room 501, Unit 2, Building 3, Sunshine Garden Community in the northern suburbs. The contact information includes two mobile phone numbers." Xiao Zhang took the medical record and saw that the man's face on the ID card photocopy was clear, with short hair and a medium build, closely matching the man captured by the lock shop's surveillance footage. He immediately took out his phone and dialed Wang Shuai's number: "Captain Wang, we've made a major discovery! We found a medical record at Little Rabbit Dental Clinic. The patient, Zheng Kaibin, matches the deceased in every way. The medical record information is complete, and there's also a photocopy of his ID card!"

Wang Shuai, on the other end of the phone, instantly snapped out of his daze and said urgently, "Great! You guys protect this medical record immediately. I'll contact forensic doctor Zhang right away to come and compare it, and at the same time, I'll take some people to Sunshine Garden Community to verify the situation!" After hanging up, Wang Shuai immediately dialed Zhang Kai's number and briefly explained the situation. Zhang Kai immediately said that he would take Xiao Lin and relevant testing equipment to Xiaobaitu Dental Clinic.

Less than an hour later, Zhang Kai arrived at the clinic with Xiao Lin. He took the medical record and the examination report of the deceased's dental filling from Xiao Zhang, carefully compared them, and then checked the surgical photos and filling parameters in the medical record using the clinic's equipment. "That's right, the filling in Zheng Kaibin's right maxillary second molar is completely identical to the filling in the deceased's tooth in terms of material, workmanship, size, and location." Zhang Kai put down the documents and said with certainty, "It can be basically confirmed that Zheng Kaibin is the victim in this murder case."

"Great! We've finally confirmed the deceased's identity!" Xiao Zhang and Xiao Li exclaimed in unison, their fatigue from the past few days instantly replaced by excitement. Wang Shuai then led his team to the clinic. Looking at the address on the medical record, he immediately instructed, "Xiao Zhang and Xiao Li, you two stay at the clinic and assist Dr. Liu with the follow-up work, making copies of relevant medical records; the rest of you come with me to the Sunshine Garden residential area to verify Zheng Kaibin's residence and contact his family."

Sunshine Garden residential complex, about two kilometers from Xiaobaitu Dental Clinic, is a mid-range community built nearly ten years ago. Upon arriving at the complex, Wang Shuai and his team first contacted the property management office. A check with the property management confirmed that Zheng Kaibin was indeed the owner of apartment 501, unit 2, building 3, registered under his name, and had lived there for five years. Property management staff stated that Zheng Kaibin usually lives alone, has a rather withdrawn personality, rarely interacts with neighbors, and they hadn't seen him in the complex recently.

"Can you contact his family?" Wang Shuai asked. The property management staff shook their heads: "The resident file only has Zheng Kaibin's contact information, not his family's. However, he occasionally has a courier pick up packages, so perhaps that courier knows his family?" The staff then provided the contact information of the courier who frequently delivered packages to Zheng Kaibin.

Wang Shuai immediately contacted the courier, who said he knew Zheng Kaibin. Zheng Kaibin usually delivered personal items, but occasionally there were packages sent to other cities. The recipient was a woman named "Zheng Kailan," and the address was in a county in a neighboring city. "I heard Zheng Kaibin mention her once; she's his sister. He doesn't seem to have any other relatives," the courier recalled. (End of Chapter)