Chen Shi said, "Don't be discouraged. Although the case seems to form a closed loop right now. I think there are still other clues to be found."

Lin Dongxue said, "Right. Zhang Xiao's criminal tactics were learned in prison. Would his accomplice also be someone he knew in prison? Prison is like a large-scale criminal skill exchange forum."

Peng Sijue pointed to the water tank where the corpse was found. "If this kind of crime wasn’t taught, can most people really think of this?”

Lin Dongxue said excitedly, "Then I'll find out who Zhang Xiao was acquainted with in prison."

Chen Shi added, "Also, this person is now outside the prison. They may have been released together."

Lin Dongxue and Xu Xiaodong left first while Chen Shi and Peng Sijue stayed there for the experiment. There were other water tanks beside them. Of course, it was impossible to test with cyanide. Peng Sijue used sodium bicarbonate and sulfuric acid which had similar properties.

When opening the water tank, everyone was extra careful, fearing that the murderer had prepared a "surprise" in it. Fortunately, the murderer wasn’t ruthless to that extent. There was nothing else in the water tank except for foul-smelling dirty water.

At the beginning of the test, Peng Sijue asked his assistant to go to the mouth of the water tank to measure the concentration of the released matter every five minutes until about 5:00 PM. By then, the assistant said that the concentration was infinitely close to zero.

Peng Sijue and Chen Shi looked down at their watches together, and then looked at each other. Chen Shi said, "45 minutes... I remember that after the police were alerted, the police came half an hour later and took a dozen minutes to understand the situation. Then we went from house to house. There was more than enough time for the murderer to cover the lid and go downstairs. Would it have been possible for them to have met the police? How did they leave the community without getting suspected?”

"Dressing up as a repairman or something?" Peng Sijue asked.

"Just then, Dongxue said..." Mentioning Lin Dongxue, Chen Shi suddenly remembered that they saw Wu Xu downstairs that day. A prisoner who was released from prison. Lin Dongxue saw Wu Xu again last night, near Zhang Xiao's residence.

Wu Xu drove a car to collect waste products, and he could enter and leave various districts at will without suspicion. Could it be?

Thinking of this, Chen Shi hurried to call Lin Dongxue, but she didn't answer. He called Xu Xiaodong. Xu Xiaodong said, "Brother Chen, I’m here at the property manager’s place watching the surveillance footage."

"Isn’t Dongxue with you?"

"She made a phone call to Captain Lin, but then she seemed to suddenly remember something, so she took a car away."

Chen Shi felt his heart drop. She wouldn’t have gone to find Wu Xu herself, right? Sometimes she is really impulsive.

The place where Wu Xu lived was the place where Lin Dongxue had previously rented. Chen Shi hurried downstairs and called Lin Qiupu while driving, asking him to bring people over there.

At the same time, Lin Dongxue had just returned to the place where she rented in the past. She thought about how Wu Xu had appeared that day, and again near Zhang Xiao’s residence last night. This was probably not a coincidence. Although she didn’t want to think about him like that, it was precisely in line with the characteristics of the suspect.

In order to verify this, she decided to go and find Wu Xu's mother, her former landlord, to ask.

After getting out of the taxi, she discovered that Chen Shi had just called and sent a few text messages, "Don't act alone! Wait for me!!!" Lin Dongxue laughed at him being overly worried. She couldn't go directly to Wu Xu of course. She was just going to ask his mother things in secret.

In order to prevent Chen Shi from worrying, she replied to him, "I’m waiting for you by the door of my previous community. Hurry up!"

Chen Shi replied, "Scared me to death. You didn’t tell me beforehand. Don’t do anything until I come."

"Okay, got it!"

It was dark and someone suddenly called out, "Miss Lin, why are you here?"

Lin Dongxue turned back and found that it was the previous landlord aunty. She smiled, "I came to do something."

"Oh, I haven't seen you for such a long time. Come over to my house and have a sit down."

"Aunty, did you go out to buy some vegetables?"

"Yeah, I went to get some to cook when I get home. Have you eaten yet?”

"No. How’s your son lately?"

As soon as she heard "your son", the landlord's face sank. "He... He ended up buying a used car and collects broken goods now. He’s earning laborious money. Haii, you know his identity wouldn’t get him a job anywhere he goes. Even restaurants wouldn’t find him to pour tea and serve water. No matter who interviews him, as soon as they hear him say he has a criminal record, he’d get rejected immediately. Haii, it's really not me resenting the government. It’s just that the words they say about rehabilitation sounds so nice and real, but when someone truly rejoins society, everyone looks down on you and you can’t even find a job. Haii, I get teary when I say too much.” At this point, the aunt wiped a few sad tears away. It seems like they were living in hard and pitiful times.

"It seems that you guys don’t have it easy." Lin Dongxue comforted. "I need to ask you something. Where did brother Wu go on the evening of August 3rd? Do you know where he went?”

The landlord aunty suddenly widened her eyes. "Huh?! Are you investigating him? At the end of the day, you guys don't take him as a good person. My son has already changed. Why can’t the government give him the opportunity to start anew? Why can’t they do that? If that's the case, what’s the point of life sentences and non-life sentences? As long as they commit a small crime, they can just be shot directly, lest they suffer when they come out! Haii."

The landlord aunty’s complaints made Lin Dongxue feel a little helpless. She said, “I’m investigating a case, but I really didn’t mean to discriminate against your son. Sometimes, I have to question hundreds of people for a single case. It’s just ordinary questioning."

"You didn’t ask anyone but came over to ask my son when he stayed at home and didn’t mess with anyone. Just what do you mean by this?!” The landlord aunty raged.

"Aunty... Could you please cooperate?"

Lin Dongxue suddenly found that the landlord’s right hand had been hidden in the vegetable basket behind her the whole time. She lifted her eyes to peek, and the aunt deliberately covered it up. Lin Dongxue couldn’t worry about being polite any longer. She directly grabbed the landlord’s right hand and found that she was texting. The text message being composed read: "Don't come home. The police have come."

Lin Dongxue looked at her in disbelief. The impression the aunt gave her in the past was always amiable and reasonable. She couldn't believe she would do such a thing.

The aunty snapped her hand back. "You won’t understand a parent’s pitiful thinking. How can I let you take my son away? Last time, you took him away for over ten years. If you take him away again, I wouldn't be able to see him again in this life!"

"Aunty, do you know something?!"

"I…"

Lin Dongxue suddenly noticed that the aunt's eyes were looking behind her. She turned around and saw Wu Xu taking big and fast strides over, clutching a handkerchief in his right hand. Lin Dongxue realized that something was wrong and immediately reached for her gun.

The aunt held Lin Dongxue's hand from behind and yelled, "Son, hurry up!"

"Let go!" Lin Dongxue shouted and hit the aunt with her elbow. Unfortunately, the aunt’s grip was so tight that she couldn't draw her gun.[1]

"Don't hurt my mother!" Wu Xu shouted and rushed over, covering Lin Dongxue's nose and mouth with the handkerchief. She knew what it was as soon as she smelled it. It was chloroform, and she’d be finished if she inhaled it.

Wu Xu grabbed Lin Dongxue's left arm and covered her with the handkerchief. The aunt hugged her right hand from behind. Lin Dongxue desperately shook her head and resisted breathing in the chloroform. People entering the housing district knew something was up and crowded around to watch, but nobody stepped forward...

1. It’s unknown why the old aunty can overpower a police officer in their prime with grip alone.