Chapter 416: Nail

Changyang City Criminal Science Center.

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

A group of people surrounded Jiang Yuan with serious expressions, as well as the evidence "long nail."

This is the most favorable evidence they have obtained so far. Just like the bullet in a shooting case, the long nail in this case carries everyone's expectations.

Apart from this, the evidence of the case is weak circumstantial evidence. Things like surveillance videos, extracted fingerprints, footprints, or some cigarette butts, bloodstains, etc., found at the scene, all belong to self-comfort items and cannot point to the murderer.

Jiang Yuan stood from the murderer's perspective and felt that long-range weapons really brought considerable advantages. If it is the same killing, hand-to-hand combat is easy to be injured by the victim, and then leave clues. Knives are slightly better, but as a melee weapon, it is also easy to be injured, and skills like bloodstain analysis are the enemy of sharp weapons.

Blunt weapons are about the same, with good and bad, mainly afraid of not being able to kill with one blow, and the risk increases sharply. In addition, the deterrent power of blunt weapons is insufficient, which will also make the victim's resistance increase sharply.

The modified nail gun, as a long-range weapon, has obvious advantages. Not only does it not easily lead to resistance, the key is that it kills quickly, and the traces and physical evidence left are very few.

The disadvantage is that it left physical evidence, such as the long nail in front of him.

Wan Baoming also introduced the situation: "This nail should not be a model dedicated to nail guns. The murderer modified the nail gun very strangely. The most common modified nail gun now fires metal steel balls, and the range and power will be greater. He did this, and it only shoots two meters at most, but the power is still considerable."

"There are three common types of nail guns: pneumatic, electromagnetic, and gunpowder. The gunpowder type is the most common, also called a cannon nail gun. It is equivalent to adding a section of blank cartridge behind the nail, similar to the blank cartridge of the weapon model, called a nail cartridge. Now, no cartridge case is left, only the nail is left, and it is not a special nail, which is very troublesome..."

"In terms of shooting residue, physical and chemical analysis and infrared spectroscopy have been done, and micro-evidence is being done, and there is no news yet."

Jiang Yuan just nodded as he listened. If he had to say, he had never seen any cannon nail guns or nail cartridges before, but from the perspective of tool marks, they are all the same. And he was looking at a random murder case, and the main reliance for running over to sell his services was Lv6 tool mark 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 are still ways to trace it." Jiang Yuan had considered this problem when he came, and said: "Can we buy the same long nail on the market for comparison?"

"There are too many types and manufacturers. There are more small factories producing nails than factories producing steel balls." Wan Baoming was a bit surprised and said: "Why not wait for the results of the micro-evidence of the nail cartridge and follow the nail cartridge?"

"This murderer has modified the nails, and the source of the nail cartridges is estimated to be very difficult to check. However, walking on two legs, it is normal to check both lines." Jiang Yuan didn't force it. His plan was indeed more troublesome, but for a case of this level, it was normal to check two clues at the same time.

Moreover, seeing the murderer committing crimes so carefully, it is really not easy to trace the whereabouts of the murderer from such an obvious loophole as the nail cartridge.

"The same long nails sold on the market... Let me think of a way to see how to buy them all." Wan Baoming felt that if this thing could find the source, it would be a clue. It's just that ordinary long nails are too common.

Jiang Yuan added: "You can buy the same long nails from every store on the Internet, and then compare them. Buy all the same long nails sold on the market in Changyang City, and then compare..."

Wan Baoming didn't expect Jiang Yuan to propose such a stupid method, and couldn't help but say: "How long will this take to compare? The key is, can it be compared?"

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

For Jiang Yuan, once the nails are in hand, putting two nails together, whether they are produced by the same factory, is just a matter of looking at them twice.

【416-25】 Wan Baoming couldn't understand how strong Lv6 tool mark identification was, still furrowed his brow, and said: "Even if it's the same factory's nails, they may be produced by different factories, and the same factory also has different batches..."

Wan Baoming couldn't understand at all how strong the tool mark identification at Lv6 was. He still frowned and said: "Even if it's the same brand of nails,

【416-27】 "Try to buy them all. If you start buying now, the possibility of buying the same batch should be relatively high." Jiang Yuan didn't care whether it was the same batch, but if a factory has different production lines...

"Try to buy as complete a set as possible. If we start buying now, the possibility of getting the same batch is still relatively high." Jiang Yuan didn't really care whether it was the same batch, but if a factory had different production lines...

"Alright." Wan Baoming could only agree.

"There are only so many clues in front of you, try it." Jiang Yuan didn't guarantee it either. He thought of a possible breakthrough path, which didn't mean he had to be 100% responsible for this path.

Wan Baoming naturally understood, and after confirming, he first arranged for people to buy nails on various platforms and various markets. Although thinking about it, he always felt it was impossible to buy all the same long nails on the market, but thinking about it carefully, the murderer probably wouldn't think that the police would break through from this aspect. At least he couldn't produce long nails himself.

If he used steel balls—using steel balls naturally has steel ball supply channels, it's hard to say which channel is easier to investigate.

"At least it's a clue." Wan Baoming put down his mobile phone, smiled at Jiang Yuan, and said: "Better than us being busy blindly these few days."

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

Everyone present was a local police officer, Wan Baoming shook his head slowly, and said: "The suspect was found based on the description of a couple who went mountain climbing. It was just close to the time of the second case, and the human evidence and physical evidence were incomplete. Now that the third case has appeared, his suspicion is very small."

"Did the suspect go to jail?"

"Yes, he went in for violent collection before. After coming out, P2P died, so he became unemployed. I thought he was retaliating against society."

Jiang Yuan hadn't seen the person, so he didn't say much, and proposed to see the corpse again.

The ultimate eyewitness of a homicide case is always the corpse. Jiang Yuan is a forensic doctor, and leaving the corpse to the end is also hoping to accumulate some information first, so that he can be targeted.

Wan Baoming had long been prepared and immediately took Jiang Yuan to the anatomy room.

After the two left, the technical police officers of the Criminal Science Center couldn't help but discuss.

"Ningtai Jiang Yuan... looks like he also feels numb." "He is a forensic doctor, now he went to see the corpse, maybe he found a direction."

"I heard that he ran to Luyang City this time and solved the case of burying the corpse by the highway, pulling out three people in one breath, and Miaohai County was also leveled by him, and the detention center was filled up."

"Otherwise, Director Yu could help Ningtai County apply for a laboratory? There are only a few spots in the whole province. However, this case is really difficult to solve."

"If it can't be solved, it will be annoying. Everyone don't sleep, wait for the murderer to come out and commit the fourth crime."

The several brigades of the Changyang City Criminal Police Detachment are now actually strictly guarding. Even if the case cannot be solved in a short time, don't let the fourth or fifth time happen again.

The atmosphere in China is different from that abroad. Police chiefs abroad who encounter serial killer cases can spit on their faces as long as they can bear the scolding. But if a serial case that cannot be controlled occurs in China, causing the leader to be furious, then anything can happen.

It is the technicians of the Criminal Science Center who also have to worry about themselves under the thunderous storm.

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

Everyone was silent for a while.

The Changyang City Criminal Science and Technology Center, speaking of which, is also built by Shannan Province with huge funds. After all, it is the main force of the provincial capital's criminal science, and it has advantages in both capital allocation and recruiting and retaining people.

In recent years, the Changyang City Criminal Science Center has performed well, it just depends on who you compare it with.

However, this time, everyone hopes that Jiang Yuan can live up to his name. This is also the particularity of the police profession. Jealousy of the virtuous and able is possible, but business must be carried by someone.

Moreover, unlike other industries, there is still a tacit understanding of "you are good, I am good, everyone is good." Between criminal police and criminals, there is almost no tacit understanding. Criminals need to pay too much, and they can't cooperate with criminal police until the chaos is rampant.

For two consecutive days, Jiang Yuan buried himself in the quagmire of evidence. The forensic dissection didn't get any useful information, but it clarified the ins and outs of some illnesses of the three old men. Obviously, knowing these now is a bit late.

The nails bought online were delivered one after another, piled up in bags. Soon, the office assigned to Jiang Yuan couldn't be walked in, and everyone started piling nails in the warehouse.

No one knows if doing this can have results, including Jiang Yuan himself.

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

There is no need to choose any auspicious day. Seeing that there are many nails bought, Jiang Yuan first called Mu Zhiyang, then called Wang Chuanxing and Tang Jia. Four people sat in the office, two people marked unpacking and kept records, one person marked classification and was responsible for recording, and Jiang Yuan sat on the table, first looking at the original long nail evidence again and again, and then putting it under the horseshoe mirror to look, and then, he looked at the nails bought one by one.

Two nails, whether they are produced by the same factory, look at them roughly, ordinary people can also distinguish some. The simplest, for example, color, some are yellow, some are silver, some are gray... In addition to this, the specific appearance and size will also have slight differences.

Because of the tolerance, the same 6.3*12 size nails, compared, will also have differences in thickness.

However, these can only screen out part of the nails. There are always some nails whose color, appearance, and size are extremely similar, and almost indistinguishable to the naked eye.

According to the assumptions of other technicians, if this part of the nails wants to be distinguished again, they have to be checked by instruments. Moreover, it is easy to prove existence but difficult to prove non-existence. Even if it is proven on a certain instrument that a certain element of the two nails is the same, it is still very difficult to prove that their sources are the same. There are always more and more complex instruments waiting there.

However, Jiang Yuan doesn't seem to be troubled by this.

He sat in front of a cleared office desk, the long nails to be checked on the left, and handed the long nails out on the right, which was considered a comparison. The whole process was not only efficient but also very quiet.

Until Wang Chuanxing started to go to the warehouse to move long nails, the technical police officers of the Criminal Science Center realized that Jiang Yuan was not joking, but really mastered a skill they didn't quite understand.

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

"Currently found three candidates, I will know the final result after reading the rest." Jiang Yuan didn't need to explain anything else to Wan Baoming, and then asked: "How is the result of the micro-evidence you did? Can you determine the source of the propellant?"

"Determined, but useless." Wan Baoming sighed. "How to say?"

"Micro-element detection, there is a small amount of aluminum powder in the residue of the propellant, and there is Arabic gum. Domestic propellant is produced by three companies in total. The propellant used by the murderer happens to come from the Nanshan Company, which has the largest sales volume. They changed the process in 1986 until now, with an annual output of 1.4 billion nail cartridges, so I can't check it anymore."

Jiang Yuan nodded as he expected, and then continued to bury his head in comparing nails. ===== CHAPTER 417 =====

Jiang Yuan nodded, having expected this, and then continued to bury his head in comparing the nails.