Since they couldn’t figure out any clues after looking at it for a while, Chen Shi said, "Let’s go and do an experiment!"

The two went to buy a white dress similar to the one in the video and went to a quiet park. Chen Shi sat on the monkey bars and got Lin Dongxue to walk by underneath it while wearing the dress. He recorded her with his phone.

"Wait, don't just walk over. The person in the video did a door-opening action." Chen Shi reminded her.

Lin Dongxue did as she was told, and they recorded the sequence three times. Then Lin Dongxue climbed up and sat next to Chen Shi to see the effects of the recordings. "Hmm, only seeing the top of the head while wearing such a beautiful dress, what a pity."

"Our purpose wasn’t to make things look good." Chen Shi laughed. "Come and compare... Your chest is really bigger and perkier."

"Get lost! Also, I think I have a bigger stride. The suspect should be shorter than me?"

"Really? But Shi Wanjun's height is similar to yours... Why do I feel like the person in the video has a heavy gait and doesn't seem like a young person? And... The chest seems to be sagging a little."

Lin Dongxue looked at Chen Shi with a disgusted face. Chen Shi said, "I'm not kidding!"

"You want to say that the suspect may not be Miss Shi. Who would it be... Wait, her mother went to look for Song Yuwen alone two days before the incident. It’s reasonable to say that relatives around the parents’ generation[1] are unlikely to visit late at night, unless… Ah, I understand now. Ms. Song was going to kill him that day, but she happened to bump into the brother of the victim , so she changed her mind. She carefully investigated the inside of the housing district and found a more secure route to avoid the surveillance monitors. Then on the evening of the 25th, she changed her clothes, put on a wig, and committed the murder."

After listening to Lin Dongxue's reasoning, Chen Shi seemed surprisingly calm. He said, "I’ve actually considered this possibility, but I can't think of a motive. As an elder, there’s no reason to kill the nephew."

"In terms of root causes, the only weakness of the second aunt is her daughter and her family."

Chen Shi nodded with pride. "You’ve learned a lot now. Yes, the key problem is still with Miss Shi. If we can find her, maybe these questions will be solved... Come, let's take a few more photos and see if we can figure out any other clues."

In the evening, Chen Shi received a call from Xu Xiaodong, saying that he saw a young woman go into Ms. Song's house. Chen Shi thought that the girl was probably Shi Wanjun. He asked Xu Xiaodong to watch closely and said that he’d arrive immediately.

Chen Shi and Lin Dongxue arrived quickly and met up with Xu Xiaodong. Xu Xiaodong complained, "I’ve been watching them all by myself, so I didn’t even dare to go to the toilet. I’m too nervous."

"Okay, you go to the toilet and have a meal as well. Leave this to us... Is she still in the house?"

"She is!"

"What are her defining features?"

"Thin and tall. Almost as tall as Dongxue, and wearing a green dress."

Lin Dongxue suggested, "Since the girl is at home right now, why not go up and meet her directly?"

"No, since we suspect this family, we shouldn’t appear too often, so as not to hit the grass and startle the snake[2]. Also, when she’s separated from her family, it will be easier to get information!"

The two sat in the car for an hour, during which Xu Xiaodong came back after eating and brought them some drinks. Chen Shi opened one and just had a sip when he suddenly saw a figure come down from the building. Xu Xiaodong said, "It's her!"

"Follow her and don't get caught!" Chen Shi instructed.

The three followed her. The facilities in the housing district were old, and it was very dark at night. They followed the girl outside. The girl called for a taxi, and they did the same in order to tail her all the way.

When the girl got out below the dormitory of a clothing factory later, Chen Shi saw that she was about to go upstairs. "Let's make an appearance!"

Lin Dongxue called out, "Shi Wanjun!"

The girl turned around and the three immediately surrounded her. When they looked at her, Chen Shi realized that she didn’t look like Shi Wanjun at all. The girl asked nervously, "Did you mistake me for someone else? I’m not surnamed Shi."

Lin Dongxue also felt that something was wrong and showed her badge. "We are the police. Let us look at your ID."

The girl took out her ID card and they checked it using the mobile police information system[3]. Her name was Ye Xiaoling. She was a local, and the photo on the ID and the person they were looking at were unmistakably the same person.

Chen Shi was silent for a while. It had all made sense. Why was it a mistake in the end? He asked, "We called ‘Shi Wanjun’ just then. Why did you react?"

"It’s late at night and I’m alone. You guys shouted from behind, so I’d look back of course."

"Do you know this person?"

"I don’t."

"But you just came out of her house!"

"What?!" The girl raised her eyebrows, "You guys have been following me all the way? I want to sue you. I went to see my aunt. What Shi Wanjun? I don't even know her! How ridiculous!"

After saying that, the girl went straight into the dormitory, leaving the three of them frozen to the spot with confused faces.

Xu Xiaodong said with embarrassment. "I'm sorry, I may have made a mistake. They were wearing similar clothes, and the build was about the same as well, so I thought that they were the same person.”

Lin Dongxue asked, "How did you know that she entered Ms. Song's house?"

"She came down to pick her up personally. At that time, the sky wasn’t completely dark, so I could see them clearly."

Chen Shi said helplessly, "Let's return and have a look again."

The three returned the same way they came and stayed in the housing district until 9:00 in the evening when the lights in Ms. Song's house were switched off. No one came down from upstairs. Xu Xiaodong blamed himself, thinking that he had made a mistake and let the real target escape.

Chen Shi said, "I don't blame you. I should have left someone here."

"Brother Chen, should I continue watching here?"

"No, let’s go back!"

He said so, but Chen Shi was unable to let the matter go. After sending Lin Dongxue home, he went back again and sat in front of Ms. Song’s building the whole night. He hadn’t been staying up at night lately. The more exhausted he got, the more he wanted to smoke. He wanted to give in and smoke a few times, but his reason still stopped him.

All night long, the building was quiet. Chen Shi didn’t have anything to do and used his phone to log in to the bureau’s general email inbox. There was an English letter sent over from Australia. Chen Shi skimmed through the letter roughly. It basically said that their university didn’t have any Chinese students enrolled there with this name.

Sure enough, studying abroad was just a lie. Chen Shi remembered that when he was talking to her over the phone, the other party was very happy to leave her personal information and seemed completely unafraid of the police investigating and verifying her details.

Moreover, this person whose name popped up frequently never showed her face. What was going on?

Chen Shi thought that there must be a key to answering all of these questions.

The sky was getting gradually brighter and Chen Shi rubbed his nose bridge to force himself to be alert. He observed everyone who entered and exited the building without blinking his eyes. Finally, he saw Ms. Song carrying a bag of garbage outside. He waited for Ms. Song to leave, then snuck over and took away the bag of garbage...

1. It’s not that elders can’t visit younger people, but they’re of different status. People of the same age are more likely to visit you than your aunt when you’re living alone. Especially, if they’re alone and it’s not because of a family gathering etc.

2. Alert them.

3. Editor IJ’s Note: Baidu says it’s something like a small tablet connected to police systems.