Luo Hao sat down in front of the computer and started typing, shaking his head. "This forum does not require email registration, so we can only know the poster's ID and related information about the computer used, such as the IP address."

Xu Yao asked again, "Then can we find out the location of the post based on this information?"

Luo Hao answered very readily, "That's possible." After that, he began to operate quickly on the computer, and within five minutes he had a clue.

"Captain Xu, we found out. This post was sent from No. 146 Yuanxiang Road, which is a coffee shop."

Xu Yao immediately stood up, took out his phone and typed out an order: "Liu Xiaobo, go and invite Judge Yang Liwu to the Criminal Police Team right now. You should take the simplest statement from him first, and when I come back, I will ask him in person."

Xu Yao took Xiao Lizi and Luo Hao with him, and asked the 110 Command Center to send two police officers who were patrolling nearby to go with them.

It should have been six hours since the post was posted, but Xu Yao still wanted to go there to take a look.

After 20 minutes, the five people gathered in front of the coffee shop, and then all rushed into the coffee shop and started to check.

The cafe is divided into two floors, and there are not many customers inside. Xu Yao asked two policemen to check the identities of the customers in the cafe one by one.

Xu Yao went into the backstage operation room of the store and found that there were four staff members in the store.

A slightly older man was the store manager. Xu Yao asked him about the posting, but he denied it and claimed that he didn't know who had posted it.

Xu Yao checked the two computers in the cafe and confirmed the manager's statement.

The patrolman also checked the identities of the customers in the cafe and found nothing unusual.

Then, it is certain that the person who posted the post had left early, and he should have used the cafe's wireless network.

Nowadays, all shops and businesses operating outside are equipped with wireless networks, so that customers can surf the Internet and have fun while shopping and dining.

Xu Yao took a quick look and found that the cafe was equipped with surveillance cameras. He immediately asked the store manager to retrieve the surveillance videos in the store. He

also screened the customers who were locked in the store before and after the posting. A total of 10 people did not bring laptops, and six of them were always looking down at their phones.

Xu Yao instructed the store manager to temporarily seal these surveillance videos and take them back to the police station for relevant surgery before detaining them.

Xiao Lizi expressed his doubts. He felt that the poster seven might not be the eight customers revealed in the surveillance. After all, the wireless network now covers a wide area. Someone could stand outside the wall of the cafe and still post online.

As expected, Xiao Lizi was also fooled. Xu Yao took the surveillance back to the criminal police team. After watching a lot of videos, he was sure that the poster was not among them.

From the actions, four people were obviously browsing, not handwriting, and the other three were just staring at the mobile phone screen for a long time, probably watching videos or TV series.

And these three people were all wearing school uniforms, they should be middle school students nearby.

This does not match the image of the person behind the scenes.

Little Leo asked again: "What if the poster saved the document in his mailbox in advance and then posted it online? In this case, he would not need to write or press any keys."

Xu Yao immediately denied it. He pointed to the video surveillance and said: "The poster is definitely not among them. You can see that these people are not only not panicked at all, but also have no intention of hiding their appearance.

If it was one of them who posted, they would know that as long as they used the wireless network, the police would have been tracking them, and they would definitely be able to find them through the fixed IP address.

So there will be more or less "I was nervous and covered my face on purpose, but it's not here."

Luo Hao also agreed with this view, "I think the poster should have posted online using the WiFi signal covering the edge of the cafe.

When I was in the cafe, I asked the manager of the cafe, and he said that there were no surveillance cameras installed on the road outside the cafe.

This is obviously an act of concealing one's identity and location."

Xu Yao nodded in agreement, and he threw this line to Xiao Lizi and Luo Hao, asking them to continue investigating, hoping to find relevant information about the poster.

Xu Yao got up and called Liu Xiaobo, asking him if he had taken Yang Liwu to the interrogation room of the criminal police team?

Liu Xiaobo nodded in agreement.

Xu Yao rushed to the interrogation room without stopping.

As soon as he opened the door, he found that Liu Xiaobo was questioning in an orderly manner in the room, and Judge Yang Liwu was sitting on the other side of the long table.

He was a little embarrassed sitting behind the table, with his hands clasped on the table. Seeing Xu Yao walk in, he immediately stood up, stretched out his hand, and greeted with a big smile on his face,

"Captain Xu, long time no see."

Xu Yao had met Judge Yang Liwu several times before. The bailiffs and police are inseparable. Although the two of them are not in the same jurisdiction, they can be regarded as nodding acquaintances.

Yang Liwu, 45 years old this year, has been working in the court for almost ten years.

In Xu Yao's impression, Yang Liwu is not as bad as the post said, saying that he accepted bribes privately and got involved in right and wrong. He should be considered to have a relatively sense of justice and an upright image.

Xu Yao closed the door of the interrogation room, directly blocking out the noise outside the corridor, and the interrogation room immediately became very quiet.

"Captain Xu, you are here. I almost only did the initial questioning, and I will leave the rest to you."

Liu Xiaobo stood up, took the initiative to retreat to the side of the stool and sat down to speak, giving the main seat to Xu Yao, who was responsible for recording.

Xu Yao extended his hand and shook hands with Judge Yang Liwu, and then he officially got to the point:

"Judge Yang, I heard from my staff that you reported the case because of a threatening letter, is that right? Did you bring the threatening letter with you?"

Liu Xiaobo quickly found a threatening letter from a pile of documents and handed it to Xu Yao, "This is it."

Xu Yao took it in his hand and examined it carefully, his eyes full of shock.

The threatening letter still contained the lead words cut from the big-character poster, and the content was "Cause and effect are cyclical, and evil will be punished with evil."

A specimen of Psoralea corylifolia was pasted at the bottom of the letter, and the signature was also two English letters YM cut from the big-character poster.

Xu Yao's brows were furrowed, and his face was very solemn, which made Judge Yang Liwu on the opposite side feel uneasy.

"Captain Xu, I have actually been paying attention to the Haidao serial murder case that you said you were investigating some time ago. YM and Psoralea corylifolia were mentioned in it.

So when I received this threatening letter, I hurriedly called the police."

Xu Yao remembered that in order to speed up the search for the manipulator behind the scenes, the leaders of the bureau had announced part of the case to the public, and these clues were indeed mentioned in it.

He looked up at Yang Liwu, a judge who paid great attention to his personal image. He had a side-parted hairstyle, a dark grey suit of exquisite quality and style, a pair of immaculate Italian custom-made leather shoes, an LV belt around his waist, and a watch on his hand that was obviously very expensive.

Looking closely, he was still dressed like an elite, but his expression was completely inconsistent with this standard civil servant outfit. His eyes were dull and flustered, his face was pale, and beads of sweat were coming out of his forehead.