wavenovel Chapter 955 Dawn
Chapter 955 Dawn
Chapter 955 Dawn
The next few days were spent in boring investigation.
Each team conducted investigations according to the established objectives. Liu Jinghui redid the time charts of several important personnel. Jiang Yuan began to receive more and more reports on trace evidence, and he read them with great interest.
It is a luxury to use trace evidence to investigate a case. The general criminal police team only uses it on key evidence in major cases. It is not that 500 yuan is not affordable, but DNA is more cost-effective.
Unlike DNA, even if the conclusion of trace evidence comes out, it can only be said that this substance exists here and now, and it is still a long way from solving the case.
In contrast, if someone's DNA is found at a crime scene, there has to be an explanation.
"How is it?" Liu Jinghui was tired of writing and drawing, so he sat down in front of Jiang Yuan and picked up a box of Zhonghua cigarettes that he had placed on the table.
Jiang Yuan smiled when he saw this, turned around and took out a cigar humidor, opened it, gave one to Liu Jinghui, took one for himself, and said as he cut it, "There are a lot of results for trace evidence, but to be specific, we may need to analyze it."
"Cigar... This will take an hour to smoke." Liu Jinghui did not continue the previous topic. He lowered his head to cut the cigar, thinking as he cut.
"That's about right. It's a good time to take a break and change your mind." Jiang Yuan said.
"I don't know how to smoke either. It's a waste."
"Me too. My dad bought it and I'm just playing with it. There's nothing wasted. It's just Cuban agricultural product. It was originally given to my dad by the merchant who sold breeding cattle when he bought some cows." Jiang Yuan lit a cigar while chatting.
Cigar smoke is ten times that of cigarettes, and it is inhaled continuously. When smoking indoors, even if the ventilation fan is spinning desperately, it only takes a short time for a conference room to become shrouded in mist and have a fairy-like air.
Jiang Yuan and Liu Jinghui smoked for a while, and they achieved the effect of 20 criminal police officers meeting together. At this time, the two people in the conference room looked at each other and suddenly had the desire to discuss.
Generally speaking, when a meeting reaches this point, it is like being a little tipsy and you can start talking about something. Otherwise, if you continue to endure it will be bad for everyone's health.
"Do you want me to help you analyze it?" Liu Jinghui took a puff of the cigar, let the smoke circle twice in his mouth, and then exhaled. What he said about not being able to smoke a cigar was just a casual remark. If the provincial department experts couldn't even smoke a cigar, how could they help the tobacco department fight crime?
"Let's take a look together." Jiang Yuan pushed the box of reports in front of him forward.
The report of a trace analysis is just two thin pieces of paper, but if hundreds of analysis reports are piled up, it will be a lot, a bit like the homework collected by bad students. You know that most of them are useless, but you still have to force yourself to read them and spend time looking for something potentially useful from a pile of useless content.
"You took many points on the windows and door locks?" Liu Jinghui didn't know how to "read" the analysis report in the scientific sense, but he had his own way of reading, which was to read Jiang Yuan.
Jiang Yuan took a sip of tea and said, "The indoor environment is quite complicated, and there are all evidences left behind, mainly clothes, bed sheets, utensils and other things. I can't see anything from the samples I took. As for the windows and door locks... the murderer must have a way to enter."
"What if the suspect opened the door to enter, or was tricked into opening the door?" Liu Jinghui reminded.
"If I was tricked into opening the door, I wouldn't hide my son." Jiang Yuan had naturally thought about this.
"This reasoning makes sense." Liu Jinghui was amused, then he became a little more serious and said, "However, if the daughter opened the door and then had a conflict with the person coming in, the mother hid her son and went out to help her daughter, and then they were both forced into the bedroom and killed, wouldn't this hypothesis better explain why the son was hidden but not the daughter?"
The smoke in the conference room became thicker.
Liu Jinghui had already had this guess, so he asked to re-investigate his daughter's network of relationships, but he didn't find a conclusion, so he didn't pursue this direction of investigation. At this time, Jiang Yuan brought up this possibility, so Liu Jinghui naturally had to add it.
Jiang Yuan listened and nodded slowly. It's just a guess. As long as there is a possibility, it's fine.
"Of course. There are many reasons why the son was hidden but the daughter was not." Liu Jinghui added, "It could also be that the daughter is too old. There are only two places in the bedroom where people can hide easily, the closet and under the bed. An 8-year-old boy could hide in the closet by piling up clothes, but with the height and size of the daughter, even if she wanted to hide, she could basically only hide under the bed, and there is nothing to cover under the bed. In this case, it is possible that the daughter hid but was discovered and pulled out."
Liu Jinghui's reasoning was very clear and had a clear direction. Jiang Yuan couldn't help but nod his head. There was indeed such a possibility.
"I get quite excited when I talk about these things." Liu Jinghui realized that the topic had been diverted. He laughed and turned around and said, "When you mentioned the way to enter the room just now, it immediately reminded me of the murder in the closed room. Hmm, what did you find from the door lock and the window?"
"Nickel, copper, chromium, carbon, iron..." Jiang Yuan showed Liu Jinghui the conclusion of the trace evidence taken from several points on the door lock.
"What does it mean?"
"How should I put it?" Jiang Yuan hesitated for a moment and said, "From the perspective of trace evidence, this conclusion cannot actually provide a decisive result. But from the perspective of investigation and analysis... although the appearance of these metal elements is normal, but the first time to obtain a lot of elements..."
Jiang Yuan simply pulled over the whiteboard, drew a keyhole on it, and then pointed at a few points. He said, "We took the lock apart because, in my opinion, there are still too many scratches in the keyhole, which exceeds the level of a normal lock. Of course, this judgment is based on experience... Next, we took some points over a large range, and then we can see that the range of various metal elements appearing in the lock is beyond the range."
If a young technician said this, it would definitely be hard to be convincing, but when Jiang Yuan said this, Liu Jinghui immediately followed his line of thought.
"Let me understand what you mean first... These metal elements you mentioned are brought by the key, not the lock itself?" Liu Jinghui grasped the key point at once.
Jiang Yuan nodded: "Elements like chromium and nickel are not from the lock itself. However, there are no typical traces of technical unlocking in this lock. So, it can be understood that it was brought by the key."
"But beyond the range? Beyond the normal range?"
"It's beyond the range of the key for this lock." Jiang Yuan said this and slapped his forehead: "Is it a new key? No, a new key wouldn't leave so many traces..."
"Wait, let me understand it again!" Liu Jinghui was very interested in any new clues. While thinking, he said, "Can we say that the new key is actually bigger than the original key, so it pokes deeper and the marks left are also deeper?"
"Well... although it's not completely like that, you can add one more thing. The new key is also a little rougher. Although the person who makes the lock will polish it, the grooves on the key are very fine. Even if it is polished carefully, it cannot be completely smoothed out. So it takes a few times to make it fit better..."
"So someone used a new key to open this door?" Liu Jinghui slapped his thigh and felt suddenly enlightened.
Jiang Yuan had to pour cold water on him and said, "It's not that simple. If it was just opening the door once, there shouldn't be so many and such extensive marks left. If it's a newly-made key, it might have to be poked more than a dozen times, or even 10 to 20 times, before leaving so many tiny marks, especially the marks of protrusion. So, it feels like a new type of lock-picking tool..."
Jiang Yuan stopped here.
Liu Jinghui asked, "New unlocking tools? Wouldn't that make the goal more specific?"
"Yes, I have been doing research in this area these days. If there is a new lock-picking tool, I think the murderer will be unable to resist using it. It is impossible for him to give up after using it only once." Jiang Yuan looked at Liu Jinghui and decided to speak more rigorously: "Of course, it is not ruled out that the murderer is so cautious, but if this is the case, it will be difficult to find the murderer through the lock-picking tool..."
"Have any new lock-picking tools been launched on the market in recent years?" Liu Jinghui suddenly asked.
"The development of locks is very slow... Well, we can also investigate along your line of thought. The murderer may not dare to sell the lock-picking tools he used, or continue to use them, but it is possible that he makes a living from them, specializes in this area, or starts a company?" Jiang Yuan was not very sure. This condition sounds simple, but it is actually very broad. In theory, all lock companies, lock-picking businesses, safe businesses, and people in the fashionable electronic lock-related industry chain are considered to be within the scope. This list is either too large or it will miss someone. It is the kind of list that even Xu Taining cannot check.
Liu Jinghui puffed on his cigar and kept exhaling thick smoke.
He was more aware than Jiang Yuan of the weak practicality of Jiang Yuan's plan. Perhaps he could do the reverse operation, first determine the list of suspects, and then see if they have any work related to locks, or suspicion and reputation for theft and burglary...
But in fact, even without Jiang Yuan’s inference, if the suspect had such experience, he would be specially marked.
It is still difficult to conduct a positive investigation, by linking the murderer to the lock, to find the murderer, because making locks, or developing a new lock, is not a profitable business, and being a burglar is obviously not a lifelong career that cannot be abandoned.
Theoretically, if the murderer really had a talent in this area, he would have been able to make a special new type of lock-picking tool that even Jiang Yuan was unsure of 10 years ago. Then 10 years later, he might have already made a name for himself in mechanics or some other field, and would not have needed to demonstrate his talent in this area.
If the murderer was someone of the same age as my daughter 10 years ago, then considering the time, the murderer would have just graduated from college by now, and might have gone to a good school for graduate studies, and it is possible that he could have studied a completely different major with his good brain.
This may be the truth...
Thinking of this, Liu Jinghui shook his head vigorously, put down his cigar, and said, "We can't think about it from this direction."
"Huh?" Jiang Yuan was puzzled.
Liu Jinghui: "What I mean is, weren't we just talking about new keys? Isn't it more reasonable to have new keys than to invent a brand new lock-picking tool that you don't even know about? Razor theory, if you can use a simple explanation, don't use a complicated one."
"A new key cannot explain the large number of fine scratches." Jiang Yuan has been thinking about this for several days.
"Indeed." Liu Jinghui picked up the cigar again and puffed on it for a while: "In fact, no matter which conjecture it is, if you think the door lock was opened abnormally, then it can be understood as a crime committed by an unfamiliar person. This can also explain the surviving little boy's statement that there were two murderers. It is more common for multiple people to commit burglary or robbery... um..."
Jiang Yuan listened to the sound and looked at Liu Jinghui: "What did you think of?"
"A burglary or robbery committed by multiple people may not be a fixed gang, but they are generally experienced people. Especially those who have the technical ability to pick locks, it is impossible for them to stop after just one case. Even if they kill someone, it is impossible for them to use a new invention to commit a crime for the first time and then give up. Thieves do not have such good self-control." Liu Jinghui shook his head. Being a thief is an addictive profession. Many people will not give up easily once they do this job. They are evergreens in the criminal system.
Liu Jinghui thought about it, smiled shyly at Jiang Yuan, and said, "I think the idea of technical unlocking can be put on hold for a while."
"Okay." Jiang Yuan agreed readily.
"Speaking of this, I have an idea." Liu Jinghui simply pulled over a whiteboard and said, "If the murderer made a duplicate key... I know you just said that a newly made key can't have so many scratches, so is it possible that the murderer made many duplicate keys... No, it should be that he made a lot of keys, poked it once, and it didn't open, so he poked it again or made a new key, and then tried again?"
Jiang Yuan's eyes lit up when he heard this: "Wait for me to see."
Having said that, Jiang Yuan immediately went to take the disassembled lock and carefully looked at the lock core under the horseshoe mirror.
The magnification of the horseshoe mirror was not high, and Jiang Yuan frowned and shouted, "Open the windows, all of them, to let out the smoke."
The smoke from the cigar was thick, which affected Jiang Yuan's observation, at least.
In fact, the windows of the conference room had all been opened, and the ventilation fans were working diligently. Liu Jinghui called people in, and each of them fanned themselves with a fan or useless documents, and threw both cigars out the door.
When the smoke cleared, Jiang Yuan looked up: "It's very possible, very possible! It's a good guess."
"Can this be confirmed?" Liu Jinghui guessed, but he never thought that this could be proved technically. He usually arrested people and brought them back for interrogation.
Jiang Yuan nodded vigorously: "The scratches inside the keyhole are the result of a repeated cycle of scratching, polishing, scratching and polishing, and then scratching and polishing again, so it looks so strange. If someone uses a newly-made key to open the door, whether he opens it or not, there will be serious scratches on the inside of the keyhole, but the process of continuously unlocking the door is equivalent to polishing off part of the scratch..."
Jiang Yuan: "The size of the keys made by the murderer varies. Some may be longer or larger than the original keys, which will create deeper scratches. The marks inside the lock core do not match the marks of the new key being used to open the lock once, or even several times, but they match the marks of multiple, irregular openings. This is a bit like the test marks found by the forensic doctor, indicating that the criminal tried to open the lock several times before committing the crime. The time for these tests may be as long as one or two months, or two or three months."
Liu Jinghui became excited after hearing this: "If that's the case, the murderer wouldn't be a complete stranger. The victim's family didn't have much money, and no valuables were lost. If the murderer was a stranger, there's no need for him to keep an eye on their home. So it seems that the murderer is very likely to have come into contact with the victim's key through some means, and then made a copy for himself, and then kept trying?"
"It's very likely." Jiang Yuan took another look at the horseshoe mirror and nodded continuously: "It's very likely that a key was first made, but it couldn't be opened, so he took it back and sharpened it with a file, then came back to try, still couldn't open it, and went back to sharpen it with a file again. This can better explain the change in the size of the key. The file made the key a little smaller and the roughness was reduced, but the length remained basically unchanged!"
"Someone familiar... or someone who is not so familiar but has access to the key." Liu Jinghui nodded continuously: "Let me make a list!"
(End of this chapter)