"It's okay, it's all work." Qi Yi responded politely, and then extracted the key words: "Wait... the camera is broken? When did it happen?"

The little brother said: "I found out last night that it was broken. There was something wrong with the transmission channel and the delay was too high. I replaced the optical cable and worked on it all morning. I just vacated it."

Qi Yi asked: "Is there a problem with just those two cameras? Are everything else okay?"

"Then I don't know. You only informed me to fix these two." The little brother said: "It's not done yet. It said that the two monitoring positions are relatively remote. Don't worry, I will solve your problem first...

…Are you trying to cool down your office because the air conditioner is broken?”

"The air conditioner is not on." Qi Yi said: "And even if it is cooled like crazy, it is unlikely to drop by more than ten degrees. I don't know the specific problem. Please take a look."

The little brother was confused when he heard: "Let's go and take a look first."

Within a few words, the two of them walked to the door of Qi Yi's office.

Opening the door, the cold air surged out instantly, making both of them tremble. The younger brother complained at the air-conditioner: "It's so cold in your office."

"It's okay now. It was much colder before than now."

The young man walked into the office, looked around, checked roughly for a while, and found the air conditioner remote control to turn on the power button.

The air conditioner beeps on and the heating mode is displayed on the panel, 26°C.

“The last time you used air conditioning was in winter?”

"Well, I don't know where the air conditioning comes from."

The boy turned off the air conditioner: "There is no way, unless you have a thermal imaging camera that can measure where the temperature is the lowest, then that's probably where it comes from."

He roughly scanned the office again, and then said: "Your office... doesn't even have a window. There are only two sources of air conditioning. If it's not the air conditioner, it's probably the ventilation fan. But it shouldn't be, the ventilation fan

Where is the refrigeration function?”

After the little brother's reminder, Qi Yi immediately reacted. He walked under the ventilation vent and looked up: "Is it possible that the ventilation fan caught some cold air and poured it into my office?"

"The question is where does such a big puff of cold air come from?"

"In other words, regardless of where the cold air comes from, is it possible?"

Qi Yi felt that he had found a vague direction and felt a little more at ease.

"If you insist on it, it's possible... Do you want me to help you take a look?"

The little brother pulled up a stool, stepped on it and took off the air intake grille, looked inside with a flashlight, and then let out a surprised voice: "Huh? This... you are really right?"

"What's wrong?"

The little brother lowered his head and said to Qi Yi: "The exhaust fan stopped. I don't know if it was burned out or the power was out. There are a lot of ice particles hanging on the fan blades, like frost."

"Frost?" Qi Yi felt that there were already a hundred thousand reasons in his mind, and there was no answer. "You mean, there is a large amount of exaggeratedly cold damp air passing through the fan blades?"

The little brother got off the chair: "Yes, and from your description, the temperature of this cold air is at least below zero. I can't handle this. I have to ask more professionals to check the situation in the ventilation ducts."

"You can't even do it?" Qi Yi asked, "I feel like you are very professional and know a lot."

He rarely praises others, which shows that this maintenance guy is indeed reliable.

"I'm just a simple learner, but this thing is beyond my ability," the boy said, "There might be something wrong with the ventilation system. This is quite a hidden danger. I suggest you report it to someone for a thorough investigation."

Qi Yi's expression also became serious and he nodded seriously.

The little brother is right. There is a problem with the ventilation system, which should not be underestimated. Today, cold wind can be poured into his office, causing the indoor temperature to drop sharply. Another day, poisonous gas can be released and bring down the entire forensic room.

"That's it, I'll continue to install the optical cable."

"Okay, I'll give it to you."

The office was very dangerous and Qi Yi didn't want to stay there.

While walking, Qi Yi suddenly remembered that his brother had just said that there was a problem with the camera: "By the way, where are the two problematic cameras? Are they next to the ventilator?"

"How do you know?" The younger brother was slightly stunned, but he responded quickly: "Wait... this is too coincidental. Does that mean the air conditioning in your office is man-made?"

There is a small blue awning in the backyard of the Criminal Investigation Detachment, and two ventilators are placed under the shed.

These two ventilators are obviously old, and a considerable part of the white paint has peeled off, revealing rusty metal with a thick layer of dirt attached.

There are several pieces lying horizontally and vertically at the junction of the air outlet and channel, and there are messy traces.

Qi Yi's face turned pale, someone had touched this place recently!

The little brother walked a few steps quickly and looked down at the marks on it: ‘Holy shit! What’s going on?!’

Qi Yi took dozens of photos from different directions, stared at the traces for a long time, and simulated it dozens of times in his mind: "Someone used tools such as screwdrivers and crowbars to pry open the air vent."

"Why did he pry open the air vent? And he pried it open and then put it back again. Why did he waste so much effort?"

Qi Yi had a headache: "It probably has something to do with the sudden coldness in my office."

"Unlikely." The little brother expressed his opinion: "This is the switchboard. If he wants to tamper with it, more than half of the entire basement will be freezing. If he wants to reach your office accurately, he has to tamper with your branch pipes."

That’s all.”

This is correct.

"Does he want to imitate the agents in the movies and climb in through the ventilation duct? This is impossible. Although the diameter of the ventilation duct is not small, it is only about the same thickness as my waist, so it is impossible to get in."

"Maybe." Qi Yi said perfunctorily, but he was thinking about the black-haired ghost he saw last night.

If it was that thing, it should be able to get in easily and successfully reach the branch duct that ventilates his office.

But what exactly was that thing? And how did it make the temperature in his office plummet?

To instantly cool down a small room of more than ten square meters by ten degrees, not only does it need to absorb a huge amount of heat, but it also requires an exaggerated ventilation efficiency. Otherwise, the air will naturally transfer heat, and the room will also have to undergo a gradual cooling process.

It was impossible to achieve this simply by relying on the ventilation efficiency of the ventilator. What Qi Yi couldn't understand was that all this happened quietly. He didn't hear any movement or feel any obvious air flow.

.

With Qi Yi's fairly limited knowledge of physics, he couldn't think of a reliable explanation at all.

"But at least it can prove that all this is man-made and not some unknown thing." Qi Yi's eyes fell on the wind again, as if he wanted to eat people.

As long as it obeys the rules, he can manage to catch it.

Seeing that Qi Yi didn't speak for a long time, the little brother was about to ask if he had discovered anything, but he saw Qi Yi's expression gradually changed, and he was a little scared for a moment.
Chapter completed!