The police sealed off the crime scene and went to the Development Zone Branch together.

As soon as they arrived at the conference room, Luo Xiaoou, the criminal investigation captain of the Development Zone Branch, hurried in and said, "Oh, sorry, Captain Tan, I had something to do at home so I took a day off."

Tan Yi heard from the police officers in the Development Zone that Luo Xiaoou's family lived in the countryside and his father was sick, so he didn't go to work today. The case was handled by the squadron leader.

He said, "It's my duty, Captain Luo, you're too polite."

Neither of them was a person who would waste time, so after a few polite words, they sat down together.

Luo Xiaoou said, "I didn't participate in the whole process, I just listened, Captain Tan will preside over it."

"Then I'll be polite." Tan Yi nodded slightly, "I'll summarize the case first, and then everyone can tell me what they think..."

The fire broke out at about 19:38, which was provided by the first passerby who discovered the alarm and immediately called the police.

The fire spread very quickly, and when each household rushed to the scene with fire hydrants and basins, it was out of control.

When the firefighters arrived, it was too late.

After the fire was extinguished, four people were found dead in the bedroom on the second floor. From the burning materials at the door, it can be inferred that someone deliberately blocked the escape route of the four people.

From this, it can be judged that this is a murder case.

The Wan family had a small truck for transporting goods, and they always kept a large barrel of gasoline at home. It is speculated that the accelerant used by the murderer was from the Wan family.

The fire started at the entrance of the supermarket, and the murderer ran away after lighting the fire.

So far, there are no witnesses to this case.

There are two possibilities for the murderer to escape the scene so quickly: first, the murderer was very lucky and no one noticed him when he entered and exited the Wan family; second, the murderer was in the neighborhood, he was familiar with the Wan family, and he could avoid the risk of being discovered by observing the people coming and going on the street.

...

Except for the stability of the Chang family, nothing unusual was found; a book was found in the Zheng family, which was a mystery novel about arson.

After Tan Yi sorted out the logic of the case, he asked Luo Xiaoou: "Captain Luo is a bystander, what do you think?"

Luo Xiaoou said: "If Chang Yaru didn't have a history of mental illness, I find it hard to believe that she would take four lives for such a small matter. Running a small restaurant business is very hard, and the willpower is often stronger than that of ordinary people... But the Wan family bought meals from his family, and there was also a prescription for tranquilizers. The evidence is very unfavorable to them."

He glanced at everyone, "Have you asked Chang Yaru about the prescription drugs? What did she say?"

A slightly older The development zone police officer replied: "Chang Yaru said that she is suffering from insomnia and sweating, and she can't sleep well. She took diazepam from the Wan family. We have checked and her medicine is all there. According to the dosage of one pill per day, the remaining amount of medicine is reasonable."

Luo Xiaoou said: "If it is really the Chang family who did it, it is not difficult to make the amount of medicine reasonable. Let's go to other pharmacies tomorrow to check whether the Chang family bought medicine from other places."

At this point, he asked Tan Yi again, "Captain Tan, do you think there is a possibility of suicide?"

Tan Yi shook his head.

There was also a commotion in the conference room, and it was obvious that they did not agree with what he said.

Luo Xiaoou smiled, "Logically speaking, the Zheng family and the Wan family have greater conflicts and are more suspicious, but we don't have any evidence at all, and it is very difficult to prove the guilt. What do you think about this?"

Wang Zheng said, "Is it possible that Wan Chunlan took his father's medicine?"

"Well, I've thought about it too."

"This guess is reasonable."

"Is it possible that the couple conspired?"

"I think this is more likely."

"Killing your own parents and brothers because of this? No way."

...

Xie Qing and Cao Haisheng sat together.

She asked Cao Haisheng, "Master, what do you think?"

Cao Haisheng said, "We should never underestimate the evil of human nature. The possibility of the Zheng family is greater."

Xie Qing nodded, "Master is right. Girls spend more time at home and have more opportunities to read books. She is very suspicious."

Cao Haisheng said with emotion, "You are right. Master has children, so he dare not think about it."

...

Tan Yi saw that everyone was discussing enthusiastically, so he did not interrupt them and talked to Luo Xiaoou in a low voice.

Luo Xiaoou took out a cigarette, took out two, and gave one to Tan Yi.

Tan Yi couldn't help but look at Xie Qing, took out a lighter, lit Luo Xiaoou's cigarette first, and then smoked it himself - it was not that he had no perseverance, but such a sudden change was not a good thing.

Five minutes later, the conference room was quiet.

Tan Yi said, "Everyone, tell us what you think."

Wang Zheng said, "Check whether the Chang family has ever committed any extreme acts. The Zheng couple, especially Zheng Jiasheng, are highly suspected. In addition, the fire came suddenly, and some people may not know the news. Expanding the scope of exclusion may yield new results."

Luo Xiaoou nodded repeatedly, "This suggestion is very comprehensive."

Tan Yi also said, "Any other opinions?"

The police officers looked at each other, and one of them said, "What Brother Wang said is what I wanted to say."

"Yes, me too."

"Most arsonists have some psychological problems. Is it possible that they are customers who have had conflicts with the Wan family?"

"I agree with this."

...

Xie Qing said: "I think we should investigate the two children of the Zheng family again. School allows them to ask for leave and skip classes. Living on campus and studying in the evening cannot prove their time."

There was a faint smile in Tan Yi's eyes.

"Child, this is a very good reminder." Luo Xiaoou agreed with Xie Qing's opinion, "It's not impossible. Children can be more cruel than us adults."

Wang Zheng also said, "If it's a child, then we'll have less trouble."

Tan Yi said, "Tomorrow morning, we'll split into two groups. One group will check the boy's high school and the other group will check the girl's junior high school. If there are no clues, we'll find a way to further investigate the Chang and Zheng couples. Captain Luo, is this arrangement okay?"

Luo Xiaoou said, "Of course, Captain Tan's arrangements are very thoughtful. Let's do it this way."

The meeting ended in less than half an hour and everyone went home together.

Xie Qing picked up Tan Yi, Cao Haisheng, and two police officers who lived in the development zone and drove them all the way.

After sending Cao Haisheng, Xie Qing and Tan Yi were the only ones left in the car.

But neither of them spoke.

Tan Yi felt that Xie Qing was tired, and it was important for him to concentrate on driving.

Xie Qing thought that Tan Yi might have to go over the case again, and wanted to give him some time to think. They

ended up in the same place.

As soon as the car entered the gate, Tan Yi said, "You leave when I get off the car, and don't stay."

He was trying to distance himself from them in front of outsiders.

Xie Qing said, "Understood."

As she spoke, the car stopped.

Tan Yi closed the car door and went straight to the yard, while Xie Qing drove back home quickly.

Chai Yu only washed the dishes, and didn't wipe the floor, so there were water stains everywhere.

Xie Qing rolled up a rag, mopped the floor without distraction, washed up and went to bed.

The next day at work, as soon as she arrived at the office, she received a call from Li Ke.

"Qingqing, the arson case in Haiqing Community has been solved, and the murderer Zheng Xiaorou has been arrested. I heard that she is only fifteen and a half years old, a minor. I am so angry, so angry, so angry!"

"Where is she?"

"In the Development Zone Branch. Captain Tan is about to go there. I will follow him and tell you when I get back."

"Okay, I also want to know why she has such a big hatred for her loved ones."

"Okay. By the way, let's go to see Yuege at noon. It will be boring if he is not here." "Okay.

"

...

As soon as the phone was hung up, Cao Haisheng came.

Xie Qing said, "Master, it's really the Zheng family's little girl. She has been caught."

Cao Haisheng was not surprised and put his backpack in the small cabinet on his desk. "As soon as you said that, I felt it was almost certain."

Xie Qing asked, "Why?"

"Of course my apprentice is the one who is so blunt!" Cao Haisheng made a joke first, and then said, "Silly child, of course it's because of rebellion."

Xie Qing slapped her forehead, "Yeah, how could I forget about the second year of middle school!"

Cao Haisheng was used to her occasionally saying a few fresh words, and did not ask any more questions. He smiled and said, "Xiao Xie, the master has got the key."

Xie Qing asked, "When do you plan to renovate?"

Cao Haisheng frowned slightly, "Just pack up and move in these two days, live here first, and then clean up slowly."

Xie Qing remembered that Cao Haisheng said that he would wait until autumn to renovate, and moving so soon must have something wrong.

But this was someone else's family matter, and Cao Haisheng didn't say anything, so as an apprentice, she couldn't ask too much.

She said, "Master, find some people to do the plumbing, paint, buy some floor tiles, and build the kitchen. It won't take a few days."

Cao Haisheng was a little embarrassed, "Xie, I'm not going to hide it from you. Master has never taken care of these things. I'm completely in the dark, and..."

He couldn't finish the next sentence.

Cao Haisheng was full of scholar's temper. If he didn't mention borrowing money, Xie Qing wouldn't take the initiative to ask.

She said tentatively: "Master, water and electricity won't cost much. We need to hire professionals to do the flooring. We can do the walls and kitchen ourselves. I know a little bit. If we don't know, we can ask someone who knows. If you are not afraid of being tired, I will help you do it. What do you think?"

Cao Haisheng immediately became energetic, "You know those too?"

Xie Qing didn't understand, but she felt that as long as she was willing to learn and work hard, it wouldn't be difficult. She said, "Don't worry, I'll take care of it."

The master and apprentice agreed on this matter, cleaned up the office together, and then sorted out the autopsy report and filed it.

At noon, Xie Qing and Li Ke met in the cafeteria.

Xie Qing asked, "What did Zheng Xiaorou say?"

Li Ke said, "After listening to her confession, I found that her mother Wan Chunlan was the culprit."

Xie Qing asked, "Why?"

Li Ke said in a pretentious tone, "My mother said that my grandparents and my uncle were the most heartless and helped them so much for nothing. They were all ungrateful people. My mother said that if my grandparents didn't agree, my family would be finished. We wouldn't even have new clothes or food. My mother said that my uncle was causing trouble for the family. If it weren't for her, my uncle and my grandmother wouldn't have agreed. . "

Xie Qing shook her head, "Don't she have her own reasons?"

Li Ke said: "She is just like her mother, going to the supermarket to get snacks every day, basically once a day. Just the day before yesterday, she was scolded by her grandmother when she went to get biscuits. This was the fuse, and then, she flipped through several books while doing her homework, and finally found the book "Psychological Black Hole." "

Zheng Xiaorou has read 90% of the books on the bookshelf. She has a special liking for books like criminal investigation, and has certain logical thinking and counter-detective thinking.

She went to the Wan family first, and after finding the diesel, she determined the method of committing the crime.

The tranquilizer was in the bedroom on the second floor, and it was very easy to get. She stole the tranquilizer when she went home for lunch at noon, and asked Wan Chunlan for two yuan, saying that she would not go home for dinner in the evening, and she and her classmates would buy bread to eat.

After returning to school, she used a pen to grind Valium into powder.

In the evening after school, she changed clothes with her deskmate, put on her deskmate's hat, and pretended to be a stranger to enter the supermarket.

She told Wan Donglai that her mother scolded her for two yuan, and she wanted to eat here, and did not let Wan Donglai and his wife tell Wan Chunlan that she was back for dinner.

Of course, Wan Donglai and his wife would not care about such trivial matters, and agreed immediately.

The Wan family usually eats at around 6:30 in the evening.

When the Chang family delivered the meal, she was waiting for dinner upstairs and did not show up.

When the clams and tofu stew were served, she sent Wan Donglai away and put sleeping pills in.

After eating eighteen Valium pills, the four people quickly felt sleepy.

Wan Donglai and his wife did not understand why, so they lay down on the bed and went to sleep.

Wan Chunshu and his parents were not shy, so he also went to bed with the old couple.

Xue Baoyi was lying on the sofa - Zheng Xiaorou had dragged her into the room.

Afterwards, she pushed the goods from the warehouse over and blocked the door.

There were usually few customers in the store at this time.

She sat in the supermarket for a long time, until 19:30, no customers came in.

So she killed him.

After lighting the fire, she rushed back to school until Wan Chunlan came to pick her up.