civil forensic

Chapter 443 Nails
Changyang City Criminal Center.

Independent small building, green office environment, suitable temperature...

A group of people surrounded Jiang Yuan and the evidence "spike" with serious expressions.

This is the most favorable evidence they have obtained so far.Just like the bullets in a shooting case, the spikes in this case carry all the expectations of everyone.

Otherwise, the evidence in the case is weak circumstantial evidence.Surveillance videos, extracted fingerprints, footprints, or some cigarette butts, bloodstains and other objects found at the scene are all self-comforting products, and none of them can point to the murderer.

Jiang Yuan thought from the perspective of a murderer, and felt that long-range weapons really brought a lot of advantages.If it is also a murder, it is easy to be injured by the victim with bare hands, and then leave clues.Knives are slightly better, but as melee weapons, they are also easy to be counter-injured. Skills such as blood analysis are the enemy of sharp weapons.

In fact, blunt weapons are similar, there are good and bad, the main reason is that they are afraid that they will not be killed in one hit, and the risk will increase dramatically.In addition, the lack of deterrent effect of blunt weapons will also greatly increase the chances of the victim resisting.

The modified nail gun has obvious advantages as a long-range weapon. Not only is it not easy to cause resistance, but the key is that it kills people very quickly, leaving few traces and physical evidence.

The disadvantage is that it leaves physical evidence, such as the spikes in front of you.

Wan Baoming also introduced the situation: "This nail should not be a special model for nail guns. The murderer changed it to a nail gun, which is very strange. Now the most common nail gun is to shoot metal balls. The range and power They will all be bigger. When he does this, he can only shoot two meters away, but the power is still quite powerful."

"At present, there are three common nail guns, pneumatic, electromagnetic and gunpowder. The gunpowder type is the most common, also called a nail gun. It is equivalent to adding a section of blank bullets behind the nails, which is similar to the blank bullets of the weapon model. It’s similar, it’s called a nail-shooting bomb. Now, there are no shells left, only nails, not special nails, which is very troublesome...

"In terms of shooting residues, physical and chemical analysis and infrared spectroscopy inspections have been done, and trace physical evidence is being done, and there is no news yet."

Jiang Yuan just nodded.If anything, he hadn't seen any nail guns or nail bullets before, but from the perspective of tool marks, they were all the same.And he saw that it was a random murder case, and the main reason why he dared to sell it was the LV6 skill, tool trace inspection.

As the saying goes, geese leave traces, not to mention such a large industrial product...

"The nail is indeed a common model, but there is still a way to trace the source." Jiang Yuan had considered this issue when he came, and said, "Can you buy the same type of long nails sold in the market for comparison? "

"There are more types and manufacturers. There are more small factories producing nails than there are steel ball manufacturers." Wan Baoming was a little surprised, and said, "Why don't you wait for the results of the trace evidence of nail-shooting bullets to come out and chase after the nail-shooting bullets?" Walk?"

"The murderer has changed all the nails. It is probably difficult to find out the source of the nail bullets. But, let's walk on two legs, let's check it all out." Jiang Yuan didn't force it. His plan was indeed more troublesome, but Well, for a case of this level, it is normal for two clues to be investigated at the same time.

Moreover, seeing the murderer committing the crime so carefully, and the nail bullets with such obvious loopholes, it is really not easy to track down the whereabouts of the murderer.

"All the spikes of the same style on the market...I'll think of a way to buy them together." Wan Baoming felt that if the source of this thing could be found, it would be a clue.However, ordinary spikes are too common.

Jiang Yuan added: "You can buy the same style of spikes in every store online, and then compare them. You can also buy all the same style of spikes sold in the market in Changyang City, and then compare..."

Wan Baoming didn't expect Jiang Yuan to come up with such a stupid solution, so he couldn't help saying: "When will the comparison be made. The key is, can the comparison be done?"

"Yes. It won't take long. As long as you buy enough nails, you can always find them."

For Jiang Yuan, when he got the nails in his hand, whether the two nails were put together was produced by the same family was nothing more than a matter of two eyes.

Wanbaoming couldn't understand how strong LV6's tool mark identification was. He still frowned and said, "Even if the same nails are from different factories, the same factory also has different batches..."

"Try to buy as much as possible. If you start buying now, the possibility of buying the same batch is relatively high." Jiang Yuan doesn't care if it is the same batch, but if a factory has different production lines... …

"Okay." Wan Baoming could only agree.

"That's all the clues in front of me, let's try it out." Jiang Yuan didn't promise, he thought of a possible breakthrough path, but it didn't mean that he was 100% responsible for this path.

Naturally, Wanbaoming also understood that after the confirmation, they first arranged for people to go to various platforms and markets to buy nails.Although thinking about it, I always feel that it is impossible to buy all the spikes of the same style on the market, but thinking about it carefully, the murderer probably would not have thought that the police would make a breakthrough from this aspect, at least he could not produce the spikes himself.

If he used steel balls—there would naturally be steel ball supply channels for steel balls, and it might be easier to investigate which channel.

"At least it's a clue." Wan Baoming put down his phone, smiled with Jiang Yuan, and said, "It's better than us being busy these days."

"What about the suspect, could it be the criminal?" Jiang Yuan couldn't see these from the file, because they were all uncertain things.

All the policemen present were their own policemen. Wan Baoming shook his head slowly and said, "The suspect was found based on the description of a couple who climbed the mountain. It was just that the time was close to the second case, and the witnesses and material evidence were not complete. Now The third case came up, and his suspicion was very small."

"The suspect has been in prison?"

"Well, those who used to engage in violent collections went in, but when they came out of P2P, they all died and lost their jobs. I thought he was taking revenge on the society."

Jiang Yuan had never seen anyone before, so he didn't say much, and asked to see the corpse.

The ultimate witness of a murder case is always a corpse. Jiang Yuan, a forensic doctor, left the corpse at the end, hoping to accumulate some information first, so that it could be targeted.

Wan Baoming had already prepared, and immediately took Jiang Yuan to the dissection room.

When the two left, the technical policemen at the criminal center couldn't help talking.

"Ningtai Jiangyuan ha... It seems that he also feels numb."

"He is a forensic doctor. Now that he has gone to see the corpse, he may be able to find his way."

"I heard that he went to Luyang City this time and solved the case of burying the corpses by the side of the highway. Three people were arrested in one go. Miaohe County also let him be leveled, and the detention center was full."

"How else can Yu Zhi help Ningtai County apply for a laboratory? There are only a few places in the province. However, this case is really difficult to solve."

"If it can't be broken, there will be troubles. Everyone, don't sleep. Wait for the murderer to come out to commit crimes for the fourth time."

Several brigades of the criminal police detachment of Changyang City are actually guarding against death.Even if the case cannot be solved within a short period of time, don't let it happen again the fourth and fifth time.

The atmosphere in China is different from that in foreign countries.When foreign police chiefs encounter cases like serial killers, as long as they can bear the scolding, they can do it themselves.But if a series of uncontrollable cases occurs in the country and the leaders are furious, then anything can happen.

Even the technicians of the criminal center have to worry about themselves under the thunderstorm.

No time to sleep, in this case, may just be the beginning.

Everyone was silent for a while.

The Changyang Criminal Science and Technology Center was built by Shannan Province at a huge cost.After all, it is the main force of the criminal department in the provincial capital city. Whether it is the allocation of funds or the recruitment and retention of personnel, it actually has advantages.

In recent years, Changyang City Criminal Center has performed well, it depends on who it is compared with.

However, this time, everyone hopes that Jiang Yuan can "be true to his name".This is also the special feature of the police profession. It is okay to be jealous, but someone must be able to carry the business.

Moreover, unlike other industries, there is a tacit understanding between hello, me, everyone.There is almost no tacit understanding between criminal police and criminals.Criminals have to pay too much, and they will not be able to cooperate with the criminal police until the chaos arises.

For two days, Jiang Yuan buried himself in the quagmire of evidence.

The forensic autopsy did not yield any useful information, but it clarified the ins and outs of some of the symptoms of the three elderly people. Obviously, it is somewhat late to know these things now.

Instead, the nails purchased online were delivered one after another, piled up in bags.Soon, the office assigned to Jiang Yuan could no longer work, and everyone began to pile nails into the warehouse.

No one knows if this will work out, including Jiang Yuan himself.

The only difference is that other technicians feel that this is a big project, but Jiang Yuan feels relaxed.

There is no need to choose any good day and auspicious day. Seeing that there are too many nails bought, Jiang Yuan first called Mu Zhiyang, and then called Wang Chuanxing and Tang Jia. Four people sat in the office, two marked the unpacking and made records, and one The person marked the classification and was responsible for the video recording. Jiang Yuan sat on the table by himself, first looked at the original long nails, and put them under the horseshoe mirror to look at them. Then, he bought the nails one by one. look over.

Ordinary people can tell whether the two nails are produced by the same factory or not.The simplest ones are colors, some are yellow, some are silver, some are gray... Besides, there are slight differences in the specific shape and size.

Due to the tolerance, the nails with the same size of 6.3*12 will have different thicknesses in comparison.

However, these also only filter out a portion of the nails.

There are always some nails that are so similar in color, shape and size that they are almost indistinguishable with the naked eye.

According to the vision of other technicians, if these nails are to be distinguished, they must be inspected by instruments.Moreover, it is easy to prove that it is not difficult. Even if a certain element of two nails is proved to be the same on a certain instrument, it is still difficult to prove that they have the same source.There are always more and more complex instruments waiting out there.

However, Jiang Yuan does not seem to be bothered by this.

He sat in front of an empty desk, started with the spikes to be checked on the left, and handed out the spikes on the right. Even if a comparison was completed, the whole process was not only efficient, but also very quiet.

It wasn't until Wang Chuanxing started to carry the spikes in the warehouse that the technicians in the criminal center realized that Jiang Yuan was not joking, but had really mastered a skill that they didn't quite understand.

"Are you really comparing long nails? Can you compare them?" Wan Baoming came in a hurry after receiving the news, looking at the temporary assembly line workshop in Jiang Yuan's office, he was a little speechless.

"Three candidates have been found so far, and the final result can only be known after reading all of them." Jiang Yuan didn't need to explain anything else to Wan Baoming, and then asked: "How about the results of the trace evidence you did? Can you determine the source of the propellant?" ?"

"I'm sure, but it's useless." Wan Baoming sighed.

"How to say?"

"Trace element detection shows that there is a small amount of aluminum powder and gum arabic in the residue of the propellant. There are only three companies producing propellant in China. The propellant used by the murderer happened to come from Nanshan Company, which has the largest sales volume. The technology they changed in 86 is now producing 14 billion nail-shooting bullets a year, and it is impossible to check.”

Jiang Yuan had known this before nodding, and then continued to bury his head in the nail.

　I was too sleepy last night, and I had to check a lot of things, so I went to bed first, and I woke up at 4 o'clock in the morning to type. Under the encouragement of guilt, it was smooth

　　
　
(End of this chapter)