Came over and found a clue after a circle? Liu Hongsheng didn't believe it, he has been engaged in criminal investigation work for many years, and his professionalism is also one of the best in the entire Luzhou City Criminal Police Team.

It's true that I'm not studying criminal investigation, but we have a plug-in, there were no eyewitnesses at the time of the crime, but there was a street tree outside the house, Shen Long leaned on the street tree just now and smoked, and he had already asked from the street tree about the crime, and it was much easier for him to look for evidence based on the crime, and it was not strange to find something useful so quickly.

"According to the information on the file, the male owner of this family is thrifty, I just looked at the ashtray, most of the cigarette butts in it have been smoked to the filter, but there is only one cigarette butt left, which is obviously not in line with the character of the male owner, and it is likely that the suspect left it; According to the results of the interrogation, the suspects we have found now have denied entering this house, so as long as we can find that this cigarette butt was left by the suspect, it must be him who committed the crime. Shen Long learned from the street tree that the suspect had smoked a cigarette before committing the murder, and the cigarette butt was thrown in the ashtray.

But how can a small cigarette butt determine who the murderer is? I remember that these suspects all had a habit of smoking, and this was not a murder weapon, and there were traces of the suspects' blood on it. Liu Hongsheng still didn't understand, even if this cigarette butt was really left by the criminal suspect, there was no way to convict him through this, he thought for a while and asked, "You mean to use this detail to interrogate those criminal suspects again?" Do something to get them to confess? ”

Anyway, Shen Long also found clues that he didn't find, Liu Hongsheng's tone changed unconsciously, for an old criminal policeman like him, a person with ability is worthy of respect.

"No, let's handle the case and not do those illegal things." Shen Long knew what he meant by the measures, sometimes the criminal police team was forced to be in a hurry, and it was normal to engage in actions such as extorting confessions, and this method also had a certain effect, but it was easy to create unjust, false and wrongful cases, and Shen Long was not willing to take them.

What's more, this method is not in line with the rules, other people do this, Li Mingjian may turn a blind eye, if he dares to do it, Li Mingjian will take the opportunity to drive him away, he will not only solve this case, but also use absolutely legal methods to solve it.

"You go back and pack your things, and tomorrow you will go on a business trip with me to Shenghai, and you may have to stay in Shenghai for two or three days." Shen Long lowered his head and got into the car and said to Liu Hongsheng.

"What are you doing in Shenghai?" Liu Hongsheng is even more confused now, could it be that the real murderer has been controlled by the Shenghai Public Security Bureau? This time in the past, the criminals were escorted back to Luzhou City?

"You'll know when you go." Shen Long didn't reveal more information, he still didn't know the details of Liu Hongsheng, and he didn't dare to guarantee that telling him the truth would cause any surprises.

When he returned to the bureau and told Li Mingjian that he was going to Shenghai on a business trip, Li Mingjian immediately agreed, he didn't think that Shen Long's going to Shenghai at this time had anything to do with solving the case, and wished that he would stay in Shenghai as long as possible, and as soon as the deadline for the 7.23 case arrived, it would be time to be held accountable, and before that, it would definitely not be conducive to him to leave Luzhou City.

I went down and made a few phone calls, made some preparations, went back to the dormitory to rest for one night, and took Liu Hongsheng to board the train to Shenghai in the afternoon of the next day, slept in the hard sleeper for one night, and arrived in Shenghai on the morning of the third day.

"Captain Qi, where is this!" When he came out of the station, he saw Qin Siyuan waiting outside, and next to him was a policeman in a police uniform.

"Come, let me introduce to you, this is Comrade Qi Tongwei, the head of the Luzhou City Criminal Police Detachment, Team Qi, this is Officer Lu Husheng of the Shenghai Public Security Bureau." Qin Siyuan introduced them.

"I've heard of Captain Qi's name for a long time, so I'm glad to meet it." Lu Husheng shook hands with him warmly, and the title of first-class heroic model is still very popular in the system.

Shen Long also introduced Qin Siyuan's identity to Liu Hongsheng, and then the four of them got into the police car brought by Lu Husheng together; Qin Siyuan was notified by Shen Long, what he was going to do this time was extremely newsworthy, and he also knew that working in the system, not only did he know how to make meritorious contributions, but also determined the attribution of credit, so as not to be robbed by others.

If he cracks the case quietly, it is difficult to guarantee that Li Mingjian will not give the credit to others, and it will be different with Qin Siyuan by his side.

"Team Qi, shall we go to the guest house to rest first, or?" Lu Husheng asked as he started the car.

"Let's go straight to the DNA lab and get down to business first." Shen Long replied that the purpose of his visit to Shenghai this time was to use DNA testing technology to determine who the murderer was, and at present, there was no large-scale application of DNA identification technology in criminal investigation in China, and only the public security system in Shenghai and other three places had DNA laboratories, so Shen Long would make a special trip.

"What the hell is this DNA lab for?" Liu Hongsheng was confused.

"This is a very advanced technology, won the Nobel Prize, human chromosomes are made of DNA, each human cell has pairs (46) pairs of chromosomes, and the human body has about 3 billion nucleotides to make up the entire living chromosome system, and the interchange and combination before the formation of biogenal cells is random; If it is not an identical twin, no two people in the world have exactly the same composition sequence of 3 billion nucleotides, which is the theoretical basis for DNA alignment identification. This detail was seen by Shen Long from an Internet book called "Officer Han", but he didn't expect it to come in handy here.

"The cigarette butts contain the saliva, the saliva, and the oral epithelial cells, which can be compared with the suspect's hair, and the identity of the smoker can be determined." Shen Long took out the evidence bag, "As early as 1984, the United Kingdom used DNA technology to crack a rape and murder case, this technology has developed vigorously in Western developed countries and is widely used in criminal investigations. ”

"And such powerful technology?" Liu Hongsheng, who graduated from secondary school, opened his mouth wide, what Shen Long said just now was a little too mysterious, and it was really beyond his understanding.