"I'm just making a guess, and in the end I have to rely on the evidence to speak." Cheng Yijie deliberately said to Mu Qingcheng, and then the topic changed, "Did your little white-faced colleague find you another place to live?" ”

He's really like a god. The word "little white face" obviously has a sarcastic meaning, Gu Hengyu's skin is relatively fair, but it is not a "little white face". Thinking of Yu Qingsheng's evaluation of Cheng Yijie, "It's not a good person when you look at it", Mu Qingcheng couldn't help laughing. "Yes, staying at his cousin's house."

"You don't have to worry about it now." Chen Yufei preemptively said.

Cheng Yijie just hooked the corners of his lips slightly, bringing a meaningful smile.

In the afternoon of the same day, Mu Qingcheng learned the bad news of Yang Ru's death, and it was Cheng Yijie who called to tell her. Yang Ru's body was found in the freezer of the Institute of Science and Technology of Xilin University, and the police analyzed that Yang Ru seemed to have inhaled excessive carbon dioxide and died in a coma. Yang Ru's body was frozen and stiff when he was taken to the hospital, and the forensic doctor from the Municipal Public Security Bureau pointed out that he may have died of lack of oxygen before he froze to death. The key to the freezer was found from Yang Ru.

According to him, after going to work at 8 o'clock in the morning, he went to the freezer for a routine inspection, and after opening the door with a key to enter, he saw Yang Ru lying on the ground.

After Chen Yufei and Cheng Yijie arrived, they looked at the surveillance camera of the freezer, and the monitor screen showed that Yang Ru came to the freezer at 3 o'clock in the morning today, but did not wear a cold-proof jacket and use a mobile exhaust fan to remove carbon dioxide in accordance with the regulations, and only wore a short-sleeved T-shirt and entered the freezer alone.

Li Ding said that the freezer uses dry ice (solid carbon dioxide) as a refrigerant, and the temperature set in the freezer is minus 22 to minus 27 degrees Celsius, and the boiling point of dry ice is minus 78 degrees, which will melt in the temperature of the freezer, increasing the concentration of carbon dioxide in the air. The medical examiner said that if excessive carbon dioxide is inhaled in a closed freezer, the blood carbon dioxide concentration will increase rapidly, and the person will be unconscious or even die within 2 to 3 minutes.

Cheng Yijie watched the video several times and said: "Yang Ru looked in a hurry, as if there was something urgent, so he let him enter the freezer in the middle of the night, and he didn't even care about safety measures." ”

"Are you sure the door is locked when you go into the freezer?" Chen Yufei asked Li Ding.

Li Ding replied yes in the affirmative.

"So, someone locked the door from the outside and locked him inside after Yang Ru entered the freezer?" Chen Yufei speculated, "But no one else appeared in the surveillance video." ”

"The surveillance footage was interrupted for more than two minutes." Cheng Yijie has already seen the clue, "Is there a power outage in the early hours of this morning?" ”

Chen Yufei's colleague Zhao Jun went to the security guard to learn about the situation, and sure enough, the power suddenly went off at about three o'clock in the morning, but it only stopped for a short time and called again, and the security guard didn't care.

"Someone pulled down the power switch, causing a power outage, and used this time to avoid monitoring and lock Yang Ru in the freezer." Chen Yufei asked Li Ding again how to keep the keys to the freezer. Li Ding said that one of the keys to the freezer was kept by him, and the other keys were distributed to several departments such as the physics department and the chemistry department of the Institute of Technology.

Ji Rongrong had already received the news and was crying heartbreakingly. Chen Yufei asked her who managed the key to the freezer in the physics department, and she said with a sob, the key is fixed on the wall in the laboratory, and those in need can take the key by themselves, as long as the person who is registered in the record book, what identity, what time to what time the key is used, what is the purpose, and then put it back in place after the key is used up.