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

After visiting Kaishengda Cosmetics Foreign Trade Company, Zhang Hui immediately led his team back to the Criminal Investigation Detachment and held an emergency meeting to analyze Chen Kaifeng's suspicions. "Chen Kaifeng's physical characteristics closely match those of the murderer. He is about 180cm tall and weighs 78kg, which is within the weight range estimated from the 43-yard footprint at the scene."

He had a direct physical altercation with Tang Hu, and Tang Hu had threatened to retaliate against him, thus having a motive for the crime; Kaishengda Cosmetics Foreign Trade Company is less than two kilometers from Chuangtian Building, and he is familiar with the surrounding environment, providing him with the geographical conditions to commit the crime. "Zhang Hui said after summarizing Chen Kaifeng's basic information and the findings of the investigation.

"Now we have sufficient reason to suspect that Chen Kaifeng is a major suspect in the crime. Next, we will conduct an in-depth investigation in the following aspects: First, verify Chen Kaifeng's activity trajectory from 6 pm to 10 pm on the day of the incident to confirm whether he has an alibi."

Second, retrieve Chen Kaifeng's bank statements and call records to see if he had any contact with Tang Hu after the conflict, and whether there were any unusual financial transactions.
Third, interview Chen Kaifeng's relatives, friends, colleagues, and neighbors to understand his personality traits, whether he has violent tendencies, and his recent emotional state; fourth, collect Chen Kaifeng's fingerprints and DNA samples and compare them with the fingerprints of the murderer and the DNA from the cigarette butts found at the scene; fifth, investigate whether Chen Kaifeng had any access to the missing elevator card from Hengtong Technology Company.

Following Zhang Hui's instructions, the investigation team immediately split into five groups to conduct a comprehensive investigation of Chen Kaifeng. The first group was responsible for verifying Chen Kaifeng's alibi. They first found the attendance records and surveillance footage of Kaishengda Cosmetics Foreign Trade Company.

Attendance records show that Chen Kaifeng left the company at 6 PM on the day of the incident, as normal. Surveillance footage from the company lobby shows Chen Kaifeng leaving the building at 6:05 PM and walking along the sidewalk. To track his movements, the team reviewed surveillance footage from the surrounding area and discovered that Chen Kaifeng did not go directly home. Instead, he went into a convenience store near the company, bought a bottle of mineral water and a pack of cigarettes, and then took a taxi towards the Chuangtian Building.

"The taxi's license plate number is Yu A·XXXXXX. We have contacted the taxi driver, who recalled that around 6:20 pm on the day of the incident, Chen Kaifeng got into the taxi in front of Kaishengda Cosmetics Foreign Trade Company, with his destination being a bus stop near Chuangtian Building," team member Xiao Li reported to Zhang Hui. "The driver said that Chen Kaifeng kept his head down playing on his phone in the car, didn't say anything, and seemed a bit depressed. Around 6:40 pm, Chen Kaifeng got off at the bus stop near Chuangtian Building and then walked into a small alley. There was no surveillance camera coverage in the alley." This alley is the only way to the back entrance of Chuangtian Building, and there are no security guards at the back entrance of Chuangtian Building, so anyone can come and go as they please.

To further verify Chen Kaifeng's whereabouts, the team retrieved surveillance footage from all intersections and shops around the Chuangtian Building. They finally spotted him in the surveillance footage of a small shop near the building's back entrance. The footage showed that around 6:50 PM, Chen Kaifeng appeared at the shop and bought a pack of "Chunghwa" brand cigarettes, matching the brand of the cigarette butts recovered at the scene. He then entered the Chuangtian Building via the back staircase. Since there were no elevator card records at the back entrance, the team could only track his movements through the stairwell surveillance cameras. The footage showed Chen Kaifeng appearing at the entrance to the rooftop around 7:10 PM, after which he disappeared into a blind spot. Around 9:30 PM, Chen Kaifeng reappeared in the stairwell surveillance footage, looking flustered as he descended from the rooftop and left the Chuangtian Building via the back staircase.

"Chen Kaifeng was present at the Chuangtian Building during the time of the incident and had ample time to confront and attack Tang Hu in the rooftop elevator lobby. His alibi is invalid!" This discovery excited all the investigators. Zhang Hui immediately ordered, "Continue to track his movements after leaving the Chuangtian Building, confirm whether he went straight home, and what his activities were like after returning home." The team retrieved surveillance footage from the area around the back entrance of the Chuangtian Building and discovered that Chen Kaifeng took a ride-hailing car home after leaving. The community's surveillance footage showed that Chen Kaifeng returned to his residential area around 10:10 PM and did not leave again afterward. This timeframe perfectly matched the forensic doctor's estimated time of death between 6 PM and 10 PM, further increasing his suspicion of being the perpetrator.

The second team was responsible for retrieving Chen Kaifeng's bank statements and call records. The bank statements showed that Chen Kaifeng's bank account had normal transactions and no direct financial dealings with Tang Hu. However, the day after the conflict with Tang Hu, a transfer of 1 yuan was made to his bank account from an anonymous account. The call records showed that Chen Kaifeng had no calls between 6 PM and 10 PM on the day of the incident, but around 10:30 PM, he had a brief call with an unknown number, lasting less than a minute. "This anonymous transfer and the unknown number are suspicious. We need to further investigate the identity of the transferor and the owner of the unknown number," said team member Xiao Wang.

The third team was responsible for visiting Chen Kaifeng's relatives, friends, colleagues, and neighbors. Through these visits, they learned that Chen Kaifeng had a volatile temper and severe violent tendencies. He had previously clashed with a neighbor over a trivial matter, even physically assaulting them. At work, he frequently argued with colleagues over work-related issues, sometimes even resulting in physical altercations. "Chen Kaifeng is very petty and holds grudges. If anyone offends him, he will definitely find a way to retaliate," said one of Chen Kaifeng's colleagues. "After his fight with Tang Hu last time, he privately told us that he would definitely make Tang Hu pay the price. I never expected him to actually do something like this." Chen Kaifeng's neighbors also reported that his emotional state had been very unstable recently, often throwing tantrums and breaking things at night.

The fourth team was responsible for collecting Chen Kaifeng's fingerprints and DNA samples. Under the pretext of assisting with the investigation, they located Chen Kaifeng, explained the situation, and collected his fingerprints and blood samples, immediately sending them to the forensic department for comparison. The forensic staff conducted the tests overnight, and the results showed that Chen Kaifeng's fingerprints perfectly matched fingerprint number 1 collected from the elevator door handle at the scene, and his DNA was also highly consistent with the DNA found on a "Chunghwa" brand cigarette butt collected at the scene! This result represented a major breakthrough in the case investigation; Chen Kaifeng was indeed the murderer of Tang Hu! (End of Chapter)