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

"If Tang Meijuan was indeed hurt by someone, then the person who hurt her and Tang Meijuan must be killed if there is any conflict between them. Whether it is emotional, financial or other disputes, we must find out clearly. My opinion is to start with the construction company where Tang Meijuan worked. In addition, some people around her should also be carefully investigated."

"The second key investigation direction is to re-examine the rooftop. The other party cannot appear on the rooftop for no reason, nor can it disappear for no reason. It must have used some other means to enter and exit the rooftop in a way that we don't understand now. Therefore, we must conduct a thorough investigation of all the equipment on the rooftop to see if there is any other way for the other party to enter and exit the rooftop."

"There are also water stains on the rooftop. It is impossible for such water stains to appear there out of thin air. They were either left by Tang Meijuan or by the suspect who murdered him. We saw from the surveillance video that Tang Meijuan came out of the elevator and went to the rooftop. She only had a mobile phone in her hand, and she didn't bring any mineral water or a water bottle."

"So we need to do two things with the water stains on the roof. The first is to test the water to see if we can extract any relevant DNA information.

Second, based on the test results of the water, we can find out where the water comes from. Is it mineral water or purified water? "

Lu Chuan's arrangement was eye-opening for everyone.

Indeed, by analyzing the material composition of water, we can determine whether the water is mineral water or purified water. We can even determine which type of mineral water it is based on the composition of the relevant substances in the water.

There is also a judgment and arrangement on the extraction of relevant DNA substances in the water, which makes everyone feel that this is also very feasible.

There was a water stain on the rooftop. No matter what the reason was, did someone spit it out after drinking it, or did someone just pour out a bottle of mineral water, or did someone wash their hands or something else happened?

But no matter what happened, this puddle of water would not appear on the rooftop for no reason. Judging from the current situation, it is very likely left by the person who murdered Tang Meijuan on the rooftop.

"At the same time, I will arrange for people to conduct inspections and other related tests on several convenience stores under Yuanfang Building. After the results come out, I want all the surveillance videos in these convenience stores to include the information of all people who have bought the relevant water into the key inspection scope."

Lu Chuan was more meticulous in the arrangements for the relevant work, and Wang Zhaokai and others carried out the relevant work in an orderly manner according to the division of labor.

That afternoon, Lu Chuan and others went straight to the rooftop of Yuanfang Building and arrived at the crime scene again.

Compared to the first time when they focused on checking the traces left by Gao Meijuan, this time the relevant personnel started on the rooftop to check whether there were any passages for people to enter and exit.

"Well... there are some relatively large ventilation ducts on the rooftop, but we are not particularly clear about the internal directions of these ventilation ducts."

The property manager did not expect the police to return to Yuanfang Building so soon and ask about the conditions of some pedestrian passages on the rooftop.

"Director Lu!"

The property management did not provide any valuable information, but the few people brought by Sun Biao made a major discovery when they were inspecting the rooftop.

"Director Lu, the ventilation duct here shows signs of having been pried open."

Lu Chuan immediately went over to check.

Sure enough, in the northwest corner of the rooftop, there was a dust cover on a ventilation duct that showed signs of having been pried open.

"The marks of prying are very clear and fresh, which means they should have been made recently. And judging from the marks, the other party should have moved it from the Libu Bridge tunnel to the outside." Lu Chuan put on gloves and observed the marks carefully. It was indeed as the criminal police who discovered the marks of prying on the ventilation cover said.

The marks are very clear, and the prying position is from the inside to the outside, which means that the other party should have started to pry the dust cover inside the ventilation duct. After opening it, they can go in and out back and forth, and this passage is relatively spacious, which can probably accommodate two adults without any problem.

"Director Lu, do you want to go down and check it out?"

Lu Chuan shook his head.

"Don't go down for now. Let's uncover the scene first and inspect all the traces here to see if there are any fingerprints left behind. After that, we will go down and check where this ventilation duct leads to. If there is really a criminal suspect entering or leaving here, there must be some biological traces left behind, and we can easily find him."

After making this discovery, the detectives immediately arrived at the scene and the relevant on-site investigation was completed about two hours later.

"Director Lu, we have collected three sets of fingerprints at this entrance and exit, and they are all relatively clear. We will compare and identify them when we return. In addition, I suggest that fingerprints of all personnel in the building be collected so that we can compare them. We also found two strands of hair inside, and we can do DNA analysis immediately when we return."

very good!

Lu Chuan did not expect to make such a big discovery during the second survey of the rooftop, and they were all directional clues.

The focus of all related work has shifted to the investigation on the rooftop, and the investigation into Tang Meijuan's interpersonal relationships has been temporarily terminated.

After making this discovery, Lu Chuan and his team immediately checked the surveillance cameras and collected fingerprints of all the people who had entered and exited Yuanfang Building on the day of the incident.

There is only one entrance and exit in Yuanfang Building. Everyone entering and exiting must pass through the surveillance in the lobby, so there is basically no way to hide yourself. Soon the collection work here was completed.

At the same time, two detectives from the Criminal Police Brigade began to compare the fingerprints.

"Director Lu, I didn't expect this case to be solved so smoothly and such an important clue was discovered."

Wang Zhaokai was in a relatively relaxed mood. At the beginning, when they judged that Tang Meijuan's death was a homicide, everyone was still quite nervous because there was no trace of the suspect in the surveillance camera. There was nothing left at the crime scene, so all the clues were not very directional.

Unexpectedly, at this moment, such a great discovery was made on the rooftop.

"Let's wait for the results. It depends on whether the fingerprint comparison can be successful."

However, things do not always go as planned.

There were more than 1000 fingerprints collected from people in the Yuanfang Building for comparison and analysis. Although it took a lot of time, after one day and one night, the entire fingerprint comparison was completed, but no one was successfully matched. (End of this chapter)