At the critical moment, Sun Jianguo broke the deadlock, walked to the old man's side and smiled awkwardly: "Old professor, there was a case in the city today, the perpetrator used sodium hydroxide, after our investigation, we found that the old professor had bought it last month, so I came to ask where the chemicals went." ”

The old man waved his hand and laughed disapprerovingly: "Hehe, it's okay, I understand what you do." You mean the sodium hydroxide I bought from Chen Wanda last month, which I used for chemical experiments, and I ran out of things as early as last month. Although this thing can be easily synthesized with other substances, I bought it because I was in a hurry to use it. ”

"I see, I'm sorry to disturb your life."

Sun Jianguo said with a smile, and then asked thoughtfully: "Old professor, is the synthesis step of sodium hydroxide complicated?" ”

"It's simple, sodium bicarbonate and calcium oxide......"

It seemed that finding Sun Jianguo's dazed look, the old man changed his words and said: "You can make a sodium hydroxide solution with baking soda and quicklime, and anyone who knows a little about chemistry will synthesize it." ”

"I see, that bothers you, let's go first."

After Sun Jianguo finished speaking, he hurriedly beckoned us to leave Jin Wei's house, and after returning to the car, Zhang Bin leaned on the steering wheel and asked, "Deputy captain, is there any need to investigate?" After working on it for a long time, this thing can be synthesized, and it is a waste of time to follow this clue to investigate. ”

Sun Jianguo said without hesitation: "Check! Anyway, there is only one Zhou's paper left, which is not so much time. ”

On the way to Zhou's Paper, Zhang Bin suddenly said: "I always feel that something is missing in this matter, but I can't remember it for a while." ”

Liu Yefang proposed: "Huh? Why don't you go back now? Maybe you'll be able to remember it when you get to the scene. ”

Zhang Bin shook his head, pointed to the factory in front of him and said, "I see that I am about to arrive at the place, and I will think about it after checking here." ”

When we arrived at the factory, we saw that the factory of Zhou's paper had been blocked by the police who came in advance, and after identifying ourselves, several of us entered the scene smoothly.

"Deputy captain, the sodium hydroxide chemicals purchased by Zhou's Paper last month have not been used so far, and we have weighed the quantity, just one hundred kilograms, which is not a lot."

Sun Jianguo's face suddenly turned ugly, and he frowned and looked at him: "The raw materials I bought last month are useless now?" Why is it useless to ask? ”

"Zhou's Paper is in arrears of workers' wages, workers are not getting their salaries and the factory has stopped production a month ago."

Liu Yefang said helplessly: "It seems that I ran for nothing again, now do you want to go back to the bureau or go to Guo Chao's house?" ”

Sun Jianguo saw Zhang Bin's meditative expression, and he shouldn't be able to remember it for a while, so he had to order him to go back to the team first and then make plans.

When he returned to the team and saw Li Jun, he reported the situation of the inspection, and when he learned that there was no gain, there was not much emotional fluctuation on his face.

Zhang Bin asked, "Captain, you seem to have expected the result a long time ago?" ”

Li Jun looked at him with a dumb smile: "Since the murderer can decompose the corpse into more than two thousand pieces to destroy the evidence, how could he not have thought that the purchase of sodium hydroxide would leave a record?" Didn't Professor Jin Weijia also say that sodium hydroxide can be made from ordinary daily necessities baking soda and quicklime, and if the murderer is highly educated, it is not uncommon to know such chemical knowledge and make it homemade. ”

Hearing this, Zhang Bin was hoarse, and after a few seconds, he asked hesitantly: "Then where should we focus on the next investigation?" This clue of the chemical can no longer be investigated, and now we don't know anything about the clues except to determine the identity of the victim. ”

"No, we still have a lot of clues, such as roughly determining the murderer's residential area, Chengdong District, the investigators of Liu Shuqian's whereabouts that day found that on the night of July 3, Liu Shuqian's last appearance was on Jiangning Road, and the first intersection on Jiangning Road to the left is the first scene of the body Songhua Street, Jiangning Road is only two hundred meters away from Songhai University, the second scene of Huangpu Street is four hundred and sixty meters away from Songhua Street, and only two hundred and sixty meters away from Songhai University, I estimate that the murderer should live near Songhai University."

"No matter how clean the murderer washed the room, not even a trace was left, but he couldn't clean the sewers and septic tanks, I have sent someone to inspect all the sewer networks in the eastern district of the city and the septic tanks inside the community, so that the scope is narrowed step by step, I don't believe that the murderer can't be caught."

Sun Jianguo's eyes lit up when he heard this, swept away the haze on his face, and asked with some excitement: "Who is responsible for this?" Can I help? ”

"There is a specialization in the art industry, I have already asked Ma Zhiyuan to take someone there, Lao Sun, you have other things to do." Li Jun said this, and his tone became serious again.

"Guo Chao doesn't seem to have any flaws on the surface, but the more such a person is, the more attention should be paid to. Although he has a family and his wife is pregnant, do you still remember the rape case of a pregnant woman who lured a young girl to her husband and raped her husband, which caused a sensation in Inner Mongolia a few years ago? You young people don't know that when we went to Inner Mongolia to study, we heard about the case, and in order to reduce the impact, the case was suppressed after the case was solved, and the media did not report on it. ”

Seeing the dumbfounded expressions of me, Liu Yefang, and Zhang Bin, Li Jun explained a little and continued.

"If there is no surveillance video clue in that case, the police will immediately determine that it is a hijacking, rape and murder case based on their work experience and professional skills, and will definitely conduct a large-scale investigation of the surrounding area. And it will definitely focus on single men with no fixed occupation, which means that families with conditions like the real murderer will be easily ignored. Based on life experience, everyone subjectively thinks that it is impossible for the husband of this family to rape the girl in front of the pregnant wife, and the pregnant wife and her husband go together to lure and rape the girl, and they will not believe it. ”

"But there was indeed such a case, and the investigators didn't believe it at the time, and finally found the sharp weapon used in the murderer's home and the relics of the murdered girl, which played a decisive role in the investigation of the case."

"There are many similarities between this case and the case in Inner Mongolia, first of all, there are pregnant women in the family, and pregnant women are a vulnerable group in people's subconscious, and if they ask for help on the road, it is easy to win sympathy, win the trust of others, and then implement the next plan. The second common denominator is that after killing the victim, the murderer used the means of dismembering the body to destroy the traces in an attempt to evade legal punishment. ”

"At present, the body of the victim Liu Shuqian has not been found, and the murderer may throw the body three or even four times, and I have sent people to keep an eye on the various traffic arteries in the east of the city to try to see if the murderer can be guarded."

"And Lao Sun, you will take someone to keep an eye on Guo Chao, this kid, to see if he has any abnormal behavior, you also know what to do, anyway, just stare at death, this matter can only be relieved if it is handed over to you. Just now I looked at the map, the family building of the city hospital is opposite Songhai University, between Songhua Street and Huangpu Street, so this kid has to make me suspicious. ”

Sun Jianguo patted me on the shoulder and said, "It's okay, then I'll just take Xiao Xu there, there are more people, and the target is big, and it is easy to be discovered." ”

"It's okay, Xiao Xu has just arrived at the unit, and he doesn't understand a lot of things, so it's good to take him to get familiar with it."

Sun Jianguo dragged me to his office, who was still immersed in shock, picked out a casual clothes to change into, and I couldn't help but ask him halfway: "Deputy team, is the case in Inner Mongolia true?" ”

Sun Jianguo saw my surprised look, and said disappreciably: "What you Captain Li said can be false?" It was really hard to believe that case back then, but the evidence was in front of us, and it had to be believed. We pay attention to evidence in handling cases, the surveillance screen captured the picture of the girl supporting the pregnant woman, the relics of the deceased were found in the pregnant woman's home, and finally the DNA extracted from the deceased was consistent with the husband of the pregnant woman, all three of which confirmed the truth of the case. ”

After finishing it, he patted me on the shoulder and comforted: "Don't think so much, do our business, we have handled more cases, and you can see more distorted and dark human nature, if you can't stand this, you should change jobs earlier, otherwise you are very tired of living, and you need me to say hello to Li Jun?" ”

When I heard the words "change jobs", I immediately shook my head like a rattle, joking, I have only been in the unit for a month, and now I say "change jobs", and it is not a laugh to death when others hear it. Thinking of this, I adjusted my expression and hurriedly explained: "No, since I decided to become a policeman, I will definitely do it, but I have grown so big, the first time I heard this kind of thing, it will be a little difficult to accept for a while, and it will be fine after a while." ”

General Sun Jianguo looked at me suspiciously, and when he saw my righteous words, he reluctantly agreed not to talk to Li Jun about it.

I was taken to the cafeteria for a meal, and then I took a bus with Sun Jianguo to the vicinity of the family building of the city hospital, and when we were looking for the best observation point, we suddenly saw a figure walking out of the family building, so we hurriedly looked for a hidden hiding place and hid.

When I saw the appearance of the person clearly, I was a little confused, it was actually Guo Chao's wife, Tian Ge. I looked at my watch, and it was already past eight o'clock, and I couldn't help but be a little puzzled: "It's all at this point, what is a pregnant woman with a big belly doing when she comes out?" ”

Sun Jianguo patted me on the back of the head and scolded in a low voice: "Don't speak!" Fucking I'm not the baby in her womb, how do I know what she wants to do? ”

Sun Jianguo and I hid in the bushes under the wall of the family building, and the shadow of the street lamp just covered our figures.