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

Chen Jiang’s words inspired everyone.

There is a clue, and it’s huge!
very good!

Chen Jiang continued.

"Let me first talk about the current investigation. We have investigated all the entrances and exits of the ventilation duct that people can enter. At the same time, the construction workers who repaired this ventilation duct in Yuanfang Building three months ago also provided some clues."

Chen Jiang displayed the construction drawings of the entire Yuanfang Building's ventilation ducts on the projector.

"The ventilation system and air conditioning system of the entire building are connected together, and the air conditioning system of the entire Yuanfang Building is all central air conditioning ventilation. The air outlets of each room are relatively small, not enough to accommodate an adult in and out. In addition, this central air conditioning ventilation system has a one-way closing function."

"To prevent the air from flowing back and causing noise, each room's air outlet has a one-way closing device, which means that the air can only come in from the other end and cannot return from this end.

Therefore, it is indeed not realistic to enter the ventilation duct system directly from the room.

We also contacted the property management and the workers who were involved in the construction of the ventilation duct three months ago. We eventually identified several points where people could enter and exit, and found some clues at one of those points.”

Chen Jiang operates the projector.

"There are eight points in the building where someone could pass through and enter the ventilation duct. We checked each of these eight points one by one and found some clues at the opening of the ventilation duct in the corridor on the 17th floor.

We also found some traces of prying and passing through in the underground 1st floor. According to the construction worker, he entered from the underground 1st floor and repaired the entire pipeline, so the traces at that location should be left by him, but he was sure that he had never entered or exited from this point on the 17th floor. "

17nd Floor?
"Isn't the 17th floor the floor where Tang Meijuan's engineering company is located?"

Wang Zhaokai asked.

Chen Jiang nodded: "Indeed.

After finding this clue, we sent people to carefully identify and inspect the ventilation pipe opening in the corridor on the 17th floor.

It is basically confirmed that someone has entered and exited the ventilation hole of this pipe and there are signs of human damage. After this, we checked the surveillance video on the 17th floor. "

There are two surveillance cameras on each floor of the Yuanfang Building, facing each other in the corridor, and can capture the panoramic view of the entire corridor.

"Theoretically, if the suspect wanted to enter the corridor on the 17th floor, he would pass by the stairwell and be captured by the surveillance camera. However, we checked and found that no one on the 17th floor, including cleaners and other staff, entered the stairwell on the morning of Tang Meijuan's murder."

No one coming in or out?
"Is it possible that the other party entered the corridor on the 17th floor in advance, or entered from another floor?"

Someone asked.

Chen Jiang nodded.

"It is indeed possible. After checking the surveillance footage on the 17th floor, we found that no one had entered the corridor on the 17th floor. We immediately checked and compared the surveillance footage on the upper and lower floors, and then checked all the people who had entered the corridor." It doesn't matter whether the other party entered the staircase from a corridor on another floor, or took the elevator from the 17th floor to another floor, and then entered the 17th floor through the corridor on another floor.

Chen Jiang has investigated everything.

"Before they jumped off the building, we searched the surveillance cameras in the entire Yuanfang Building and found a total of seven people who entered the corridor on different floors."

The other party entered the corridor. Although there was no surveillance inside, Chen Jiang and others were able to capture the time when the other party came out.

"Among these people, there are cleaners and ordinary staff. We timed the time they took to enter the corridor. If they were criminal suspects, they would have crawled in through the ventilation duct on the 17th floor and climbed all the way to the roof. It would have taken at least half an hour."

Although the ventilation duct is large enough for an average adult to pass through, one must be very careful throughout the entire process, otherwise one will be discovered if any noise is made.

Another thing is that there is a steep slope for a distance from the ventilation duct on the 17th floor to the ventilation duct on the rooftop, and climbing is very difficult.

The pipeline robot has monitored and recorded all the internal pipeline conditions, so after Chen Jiang and others' analysis, if someone wants to climb from the 17th floor to the top floor, then it will not take a few minutes to climb the stairs normally, but at least half an hour.

"Adding the time it took for the other party to come down from the rooftop, this time may have lasted at least one to one and a half hours, because he also had to kill Tang Meijuan, so the time must also be taken into account. Therefore, we conducted a time investigation on all the seven people we have found."

"But the result was very bad. The time these seven people spent in and out of the corridor ranged from more than ten minutes to only four or five minutes."

"From the time point of view, the other party returned to the surveillance range in such a short time, which basically meant that they had no time to commit the crime. In addition, we have questioned all seven people. The cleaner went in to clean the stair handrails, two people went in to smoke, and two normal people went in to make phone calls."

“Have all seven been investigated?”

Chen Jiang nodded: "We have reviewed all the surveillance footage before Tang Meijuan's accident on the morning of the incident. These seven people were excluded. They were not involved in the incident for long periods of time and each had their own reasons. For example, we checked the call records for those who made phone calls, and we also found an ashtray in the stairs for those who smoked. These people often went to the corridor to smoke, so they put a mineral water bottle in it, which contained cigarette butts."

When Chen Jiang said this, there was silence in the conference room. They finally got a clue, but in the end, this clue was cut off like this?
Wang Zhaokai suddenly spoke.

"Have you checked yesterday's surveillance?"

Since Chen Jiang said there were clues, and the clues were very big, it is impossible that nothing was found after searching so far.

Sure enough, Chen Jiang nodded excitedly.

"Captain Wang, we checked, and when investigating the relevant surveillance video from yesterday, we found an important clue."

General Chen was controlling the projector, and the screen showed the surveillance footage in the corridor on the 17th floor.

"Everyone, this is the surveillance video from the floor where Tang Meijuan worked when we got off work yesterday afternoon. Everyone remember this man. He left the corridor at 4:28 pm." (End of this chapter)