After collecting the teachers’ fingerprints, they left the school. Wei Zengmali was still talking to Chen Shi along the way. "Uncle, Yueyue’s results are so good. Do you often give her special rewards?"

"She mainly gets to eat well. I usually cook, and I don't repeat the same dishes."

"Wow, you cook your own food? How amazing!"

"Show-off in disguise!" Lin Dongxue smiled. "Old Chen, I have something to talk to you about."

Chen Shi said to Tao Yueyue, "You and Mali should go and buy ice cream."

Tao Yueyue understood and took Wei Zengmali away with her. Lin Dongxue asked, "Do you have any suspicions towards any of those teachers?"

"Not right now."

"Actually, you do but you’re just afraid that you’d mislead me."

"Haha, Dongxue really understands me."

"But everyone thinks that the date of Miss Lin's disappearance was October 1st. When we were with her parents just now, her father mentioned that he had asked Lin Xiaoxiao to go home for dinner that day. Lin Xiaoxiao had entered the housing district and given him a box saying that she had some things to do and couldn’t come home for dinner before taking her leave.”

"What box?"

"It was just a foot-washing machine that she had bought for her parents."

"What was the time?"

"About 4:00 in the afternoon. That is to say, her father was the last person to see her."

"As a result, there are three witnesses who proved that she was still alive on October 1st."

"Correct!"

Chen Shi felt that it was a bit strange. They were all eyewitness testimonies. If Teacher Lin wanted to go somewhere, wouldn’t it be best to leave on September 30th?

She had gone to school on October 1st and didn’t do much. It seemed that she had just done it to be “seen” by people. What’s more anomalous was that she had actually left her mobile phone behind in order to leave a message, when she could have left a slip of paper instead.

Abnormal!

All three eyewitness testimonies regarding October 1st were questionable.

Chen Shi said, "I want to take a look at the surveillance footage near the school and her house to verify these witness testimonies."

"Didn't you promise to keep Yueyue company tonight?"

Chen Shi looked helpless. Tao Yueyue and Wei Zengmali returned with three chocolate ice creams. Tao Yueyue gave one of them to Lin Dongxue. Lin Dongxue gratefully said, "Thank you!"

"Yueyue, I have to work overtime tonight." Chen Shi said.

Tao Yueyue behaved calmly, "Oh, then I will go to Mali's house to do my homework!"

Wei Zengmali said happily, "Just eat dinner at my house. You can also help me with my homework."

"Then I’ll trouble you Mali... Yueyue, do you still have pocket money? I'll give you a little!"

"Uncle Chen!" Tao Yueyue said in a tone that reminded him.

"Oh, yes, I forgot!" Chen Shi smiled. Remembering the previous promise, he hugged Tao Yueyue and patted her head. "I will pick you up tonight."

"Don't come back too late."

Then, Lin Dongxue and Tao Yueyue hugged each other, and the two children left side by side. Chen Shi then drove away with Lin Dongxue.

After getting the surveillance footage of the housing district where Teacher Lin’s father lived, the two returned to the bureau. Many people in the second team were working overtime in order to watch the footage. Xu Xiaodong was eating cup noodles by the computer. Chen Shi patted his shoulder from the back. "Any findings?"

"Although there isn’t any footage for October 1st, Teacher Lin did leave the school normally on the evening of the 30th."

"Let me see."

Xu Xiaodong rewound to that segment, and there was indeed an image of Teacher Lin walking out with another female colleague at 6:00 in the evening.

Everything was very natural.

Chen Shi found a computer to play the surveillance footage of the housing district and looked at it. Suddenly, an object flew into the screen. The screen vibrated a little and then the whole screen turned uselessly towards the other side and didn’t capture the entrance to the housing district at all. The footage thereafter was all of bushes.

"What's going on?" Lin Dongxue said.

"I'll rewind it."

He rewound to that segment, paused, and then played it frame by frame. Chen Shi paused it again at a certain frame. The suspicious object in the picture was already very close. There were some regular geometric lines on it. Lin Dongxue said, "This wouldn’t be a football, right?"

"It seems too coincidental. I don't know which youngster would kick the ball at the camera, causing it to turn so that the key footage wasn’t captured."

"The camera is probably still crooked, but the security guard didn’t discover it ."

Chen Shi contemplated it silently for a long time before saying, "Let's take another look at the school's footage on September 30th."

When Chen Shi played the video, Lin Dongxue stared at the screen and asked, "What are you suspecting? Why watch this footage? There is a lot of surveillance footage near the school on October 1st that we have brought back."

"I’ll tell you later!"

Chen Shi had a vague guess. Someone had tampered with the time. He reached out and pressed pause. The screen stopped at the scene where Teacher Lin and her colleague were walking out side by side.

After thinking about it for a while, Chen Shi fast-forwarded the footage. A large number of students were heading out. The scene was very messy, and the pixels were a little blurred.

Lin Dongxue didn't know what he was looking for, she got up and poured him a glass of water, but Chen Shi suddenly grabbed her hand. "Here!"

"What is it?"

Chen Shi enlarged the image and pointed to a little girl. "This is Tao Yueyue."

Lin Dongxue smiled, "So you were watching her."

"Tao Yueyue was wearing jeans, but this pair of jeans was splashed and dirtied by a car on the way home from school on September 29th. I washed them myself. She was wearing a plaid skirt on September 30th."

"Perhaps..."

"Someone overwrote the surveillance footage on September 30th with the previous day's footage."

"But the timestamp shows that it was September 30th."

Chen Shi pointed to the upper right corner. "This '1' is a bit blurred. It had been tampered with. You just need to add a layer in a video editing software and overlay it, export it, and change the name. It will become the surveillance footage for September 30th."

"I'll look for the surveillance footage on September 29th!"

Lin Dongxue found that segment of surveillance and played both of them at the same time. She was surprised to find that the two days of surveillance were exactly the same, except for the date.

"Everyone, there is a major discovery!" Lin Dongxue clapped.

Everyone came around and expressed their surprise at this discovery. A police officer said in shame, "I overlooked it. I watched both of these footages. I didn’t expect them to be the same."

"The footage at the school entrance is almost the same every day at first glance. We don't blame you!" Chen Shi said.

"But why switch the surveillance on September 30th? Didn’t she go missing on October 1st?”

"This shows that something had happened on September 30th. Maybe this day was the real date when Teacher Lin really disappeared."

"No, there were three people who had witnessed seeing Teacher Lin on October 1st. Even if the school worker and Teacher Liu lied, her father couldn’t have done so!" Xu Xiaodong said.

Chen Shi went silent. How did this happen?!

He increasingly believed that this was by no means an ordinary case. The murderer had used some trick to push the date she had gone missing on back by one day. This showed that the starting point of the incident was a sudden occurrence which couldn’t be changed itself, so the murderer had to tamper with the timing.

After a long silence, Chen Shi asked, "Who was the criminal who stole the Zhonghua cigarettes?"