Chen Jiang’s words excited everyone.
There are clues, and they’re huge!
very good!
Chen Jiang continued.
"Let me talk about the current investigation first. We have investigated all the entrances and exits on the ventilation duct that allow people to enter. At the same time, the construction workers of the ventilation duct that were repaired in the Yuanfang Building three months ago also provided some clues. .”
Chen Jiang displayed the construction drawings of the ventilation ducts of the entire distant building 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 central air-conditioned. The air-conditioning outlets in each room are relatively small, not enough to accommodate an adult's entry and exit. In addition, This central air conditioning ventilation system has a one-way closing function.”
"In order to prevent the air flow from flowing back and causing noise, the air outlet of each room has a one-way closing device, which means that the air flow can only come in from the other end and cannot return from this end.
Therefore, it is really unrealistic to directly enter the ventilation duct system from the room.
I also contacted the property management company and the workers about the ventilation duct construction three months ago, and finally identified several points where people can enter and exit, and they are at one of them. Some clues were found. ”
Chen Jiang operates the projector.
"There are eight points in the entire building where people can pass through and enter the ventilation ducts. We investigated these eight points one by one and found some clues in the opening of the ventilation duct in the corridor on the 17th floor.
We also found some signs of prying and passing on the negative 1 floor. According to the construction worker, he entered from the negative 1 floor and repaired the entire pipeline, so the location of that place The traces should have been left by him, but he definitely said that he had never entered or exited from this point on the 17th floor. ”
17th floor?
“Isn’t the 17th floor the same floor where Tang Meijuan’s engineering company is located?”
Wang Zhaokai asked.
Chen Jiang nodded: "That's true.
After finding this line, we sent people to carefully screen and inspect the ventilation pipe opening in the corridor on the 17th floor.
It can basically be confirmed that the vent of this pipe has indeed been entered and exited by someone, and there are traces of man-made damage. After this point, we reviewed the surveillance video from the 17th floor. ”
There are two surveillance videos on each floor of the Yuanfang Building. They are facing each other in the corridor and can capture a 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 surveillance cameras. However, we checked that there were no personnel on the 17th floor, including cleaning staff, on the morning of Tang Meijuan's murder. Enter the stairwell on the 17th floor through the stairs with other staff.”
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 we reviewed the surveillance on the 17th floor and found that no one had entered the corridor on the 17th floor, we immediately reviewed and compared all the surveillance on the floors above and below, and then conducted a comparison of all the people who had entered the corridor. Investigation." No matter whether the other party entered the stair passage from the passage on other floors, or took the elevator from the 17th floor to another floor, and then entered the 17th floor through the corridors of other floors.
Chen Jiang has investigated everything.
"Before they jumped from the building, we searched and monitored the entire Yuanfang Building and found 7 people who entered the corridor on different floors."
The other party entered the corridor. Although there was no surveillance inside, the time when the other party came out could be captured by Chen Jiang and others.
"These people included cleaning staff and ordinary staff. We timed the time they entered the corridor. If the other party was a criminal suspect, he would climb in through the ventilation duct on the 17th floor and climb to the top of the building. The time consumed is at least half an hour. ”
Although the ventilation duct can allow ordinary adults to pass through, you must be careful during the whole process, otherwise people will find out if you make any noise.
Another thing is that there is a steep slope from the ventilation duct on the 17th floor to the ventilation duct on the rooftop. It is very difficult to climb.
The pipeline robot has monitored and recorded the entire internal pipeline situation, so after the research and judgment of Chen Jiang and others, if someone wants to climb from the 17th floor to the top floor, then. This time is not the few minutes it takes to climb the stairs normally, but at least half an hour.
"In addition to the time it took for the other party to come down from the rooftop, this time may last at least an hour to an hour and a half, because the time he had to kill Tang Meijuan in the meantime must also be included in the calculation, so we have to pay attention to all the things we have discovered. All 7 people conducted time surveys.”
"But the result was very bad. These seven people spent more than ten minutes in and out of the corridor, and only four or five minutes less."
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"From a time point of view, the other party returned to the surveillance area in such a short period of time. Basically, there was no time to commit the crime. Moreover, we have interviewed all seven people. The cleaning staff went in to wipe the stair handrails. Two of them One person went in to smoke, and two normal people went in to talk on the phone.”
"Have all seven people been investigated?"
Chen Jiang nodded: "On the morning of the incident, we had already checked before Tang Meijuan's accident. All the surveillance systems excluded these seven people for a short period of time, and they all had their own reasons. For example, we checked the call records of those who called, and others such as Those who said they smoked, and we also found an ashtray in the stairs. These people often go to the corridor to smoke, so they put a mineral water bottle in it with cigarette butts in it.”
When Chen Jiang said this, there was silence in the conference room. He finally got a clue, but was the clue just broken?
Wang Zhaokai suddenly spoke.
"Have you checked yesterday's surveillance?"
Since Chen Jiang said there were clues, and the clues were huge, it would be impossible to find out nothing.
Sure enough, Chen Jiang nodded excitedly.
"Team Wang, we checked, and while investigating the relevant surveillance video yesterday, we found a major clue."
General Chen controlled the projection, and what appeared on the screen was the surveillance footage from the corridor on the 17th floor.
"Everyone, look at this surveillance video from the floor where Tang Meijuan worked when she got off work yesterday afternoon. Everyone remembers this man clearly. He left the corridor at 4:28 pm." (End of Chapter)