The detachment leader's office. Qin Yong was crossing his legs, holding a small teapot, and humming popular songs from thirty years ago.
Murder is not terrible, as long as you can solve the case, you are a good police officer. From being a front-line criminal police officer to now, Qin Yong has experienced thousands of cases, large and small.
There are almost a dozen or twenty murder cases every year. It can be said that he was trained in the mountains of corpses and seas of blood.
Facing the murder case, Qin Yong has long had a normal mind. When handling a case, it's time to be nervous and work overtime. Now that the case is solved, it's time to relax.
In fact, there is a reason why being a police officer does not last long. When a case comes, adrenaline surges, and it is common to stay up for days and nights without sleep.
The case was closed, and everyone seemed to be paralyzed. Qin Yong was leaning on the back of the chair, humming a tune, squinting his eyes and about to fall asleep.
I'll go to the bureau tomorrow to report the case, and I can get off work at noon... Buzz buzz. The vibrating sound of his cell phone woke Qin Yong who was just about to fall asleep.
"Old Liu, are you done at the scene?" The first crime scene is the most focused part of the investigation in all murder cases.
"We're almost busy here, but we discovered a new situation."
"Oh? What's going on?"
"Zhang Wei...maybe not the murderer!" Not the murderer? Liu Guodong's words were like an ice pick, piercing Qin Yong's heart.
The drowsiness I felt just now dissipated instantly. Qin Yong jumped up from his chair, and his voice rose an octave: "What did you just say?" Liu Guodong's voice was low: "Zhang Wei, it is possible that he is not the murderer." Liu Guodong, who was far away in cold storage No. 8, was wrapped in a coat. , freezing nose and runny nose.
The work on site is nearing completion and will be over soon. After collecting on-site evidence, you can have a peaceful sleep when you return.
As a result, a phone call from Lu Chuan meant that all work might have to start again.
"Did you find anything at the scene?" Qin Yong's first reaction was what evidence Liu Guodong found at the scene.
But Zhang Wei had already given up, and his account of the crime was very detailed, and it didn't look like he was taking the blame for someone else.
"Nothing was found on this side of the scene, it was on Lu Chuan's side."
"He collected a drop-like blood stain from the body fragments. The blood type did not match the blood type of the deceased. He speculated that it should have been left by the murderer."
"Before we caught Zhang Wei, Lu Chuan did a blood stain analysis on Drip's blood type."
"But just after Lu Chuan collected blood from Zhang Wei, he found that his blood type is type A, and the blood type dripping blood is type AB."
"Zhang Wei, it's very possible that he's not the murderer!" After hanging up the phone, Qin Yong put on his coat and went straight to the current exploration laboratory.
When Liu Guodong called Qin Yong to report, Lu Chuan was collecting DNA information from the blood stains on the corpse.
From a technical point of view, Lu Chuan only provided evidence from current exploration discoveries. As for who the evidence points to, that is not Lu Chuan's concern.
Therefore, after determining that Zhang Wei's blood type did not match the blood type of the blood stain, Lu Chuan focused on extracting DNA information from the blood stain.
When Qin Yong arrived, the DNA information dripping from the blood had just been extracted.
"Xiao Lu, Lao Liu said you made some new discoveries here?" Looking up, he saw Qin Yong coming in. Lu Chuan nodded and continued to operate the computer.
Compared with the past few months, Lu Chuan was no longer the newbie who always saluted everyone he met. Being a first-class meritorious recipient allowed Lu Chuan to accumulate enough status.
Now, no one is talking about the time when Lu Chuan joined the police. The entire criminal investigation detachment knew that Lu Chuan was an expert in fingerprint identification and analysis.
This is one of the most sought-after technical abilities. Maybe one day I will have a fingerprint on my hand and need help.
"Team Qin, we have discovered something." Lu Chuan explained in detail the inconsistency in the blood type comparison.
"According to Zhang Wei, he killed Wang Guizhi alone, and then dumped the body in a taxi alone."
"In this case, it is impossible for Wang Guizhi's body to be stained with the blood of anyone except herself and Zhang Wei."
"Where did this drop of blood come from?" A drop of blood is insignificant, but sometimes it is enough to overturn the entire case.
What the police pay attention to when handling a case is not the thoroughness of logic. Logic makes sense, but reality may not make sense.
What happens in reality is not entirely logical. For example, Zhang Wei's motive for killing, according to his explanation, was that he killed the person because they had a quarrel.
This is obviously not logical. But reality may happen. Therefore, in any case investigation, logical reasoning is basically an auxiliary analysis.
The final thing to look at must be the evidence. The witnesses and physical evidence must be complete, and the chain of evidence must be complete, and there must be no contradictions.
According to Zhang Wei's narrative, the motive for the murder, the murder weapon, the crime scene, the process and technique of dumping the body, etc., can all form a closed loop.
However, this drop of blood on the corpse caused a loophole in the closed loop. Of course Qin Yong knew what Lu Chuan meant.
The source of this drop of blood must be found.
"How about DNA information comparison?" Lu Chuan had just entered the information into the system and was comparing it. When Qin Yong asked, the result came out.
"Huh?" After glancing at the report, Lu Chuan was slightly startled: "Is the information from the same source?"
"What information comes from the same source?" Qin Yong took a step forward when he saw the DNA comparison results.
"Oh," Lu Chuan clicked the mouse and printed the report: "When I collected Zhang Wei's blood, I also collected his hair and did a DNA information test."
"The blood stains on Wang Guizhi's corpse show that it has the same origin as Zhang Wei's DNA information, and there is a parent-child relationship between the two." Parent-child relationship?
"When Zhang Wei committed the murder, his son was also present?" Qin Yong immediately understood what was going on.
"Even... is it possible that the murderer was not Zhang Wei at all, but his son?"
"Zhang Wei...is taking the blame for his son?" Lu Chuan shook his head. These two conclusions cannot be distinguished by technology.
But now that we have this clue, it's not difficult to track it down. Zhang Wei said that he had been driving before the murder, and he would know by investigating the trajectory.
And according to preliminary investigation results, Wang Guizhi took the bus home after get off work. If you check why she got off the bus and took a taxi, you will understand everything.
After taking the report, Qin Yong left the field investigation laboratory and made a phone call as he walked: "Zhang Hui, interrogate Zhang Wei again!" Lu Chuan packed up the instruments and the remaining test materials, put on his coat and left.
The on-site work at Cold Storage No. 8 has not been completed yet, and Lu Chuan can still catch up with the finishing touches. trial room.
Facing the DNA information comparison report in Zhang Hui's hand, Zhang Wei said nothing.
"Zhang Wei, did you kill the person?"
"Don't think that if you don't say anything, there's nothing we can do."
"We are already looking for the people who were in your car three nights ago. We will know if you drove the car that day or your son drove it." While Zhang Wei was being interrogated for the second time, he told Zhang Wei The arrest of his son Zhang Xuanrong was also launched simultaneously.
