Chapter 182: Old Trade

Solving cold cases through fingerprints was already Jiang Yuan's old trade.

The plaque for the second-class merit was still drying at the door, being wiped shiny by his father day by day.

Having done so many cold case fingerprints, as soon as Jiang Yuan saw this bloody fingerprint on the leather jacket, he felt there were conditions for comparison.

This was a kind of self-confidence based on personal ability.

First, the clarity of bloody fingerprints is usually okay. Of course, this fingerprint was found on a leather jacket, and the clarity was slightly affected, but it was still better than the conditions of most latent sweat fingerprints.

Second, although the fingerprint was only one-third the size and lacked a center, it had fingertips. This condition was a very personalized condition.

Normal trace examiners, if they saw a fingerprint without a center point, or the center point was blurry, would just give up and not do it. Because fingerprint impressions with such conditions are very difficult to check.

But for Jiang Yuan, as long as he could correctly judge the position of the center point, and the texture lines around the center point were clear, he had the confidence to do such fingerprints. The success rate was only a little lower than fingerprints without a center point.

If it were doing a current case, naturally, the better the fingerprint conditions, the easier it would be to do.

But having done so many cold cases, a most obvious piece of knowledge had long been laid out: for cold cases, the better the fingerprint conditions, the less meaningful they are.

Fingerprints that anyone can check are like lick-dogs that lick everyone they see; their owner doesn't exist.

Of course, the difficulty of the fingerprint in front of him was also obvious.

Jiang Yuan downloaded the fingerprint image to the computer, looked at the picture, and didn't start immediately.

At this time, a system message flashed before his eyes:

Task: Break the Suspicious Case

Task Content: Solve the 405 Xu Hai case

Jiang Yuan checked, and the 405 Xu Hai case was exactly the case he had just selected.

This way, it was also worry-free; there was no need to consider whether to choose other cases if this case encountered difficulties.

Just focus on smashing this case.

Jiang Yuan rubbed his hands, the old rule: regardless of whether the fingerprint conditions are good or not, PS the picture first.

The old saying goes well: PS rolls three times, and the beauty can't stand still.

After the fingerprint is PSed, it's like a leader who has drunk Maotai; they are always going to reveal their true colors.

Jiang Yuan didn't want much either. Normally, he would draw 15 feature points on a complete fingerprint. If he could get 8 fingerprint points on one-third of a fingerprint, he would have the foundation for comparison.

The old high-performance host roared.

Wu Jun heard the sound and looked up: "Did you choose a case?"

"405 Xu Hai case." Jiang Yuan said.

"Tell me the situation of the corpse, and I'll know." Wu Jun stood up and lit a cigarette by the way.

Jiang Yuan picked the main points and said: "The corpse was found by the country road in Litang Township. When found, the corpse was about 8 meters away from the country road, blocked by trees and vines. The corpse was highly decomposed, with knife wounds on the abdomen and chest..."

"Ah, I know, is the deceased a self-employed person selling clothes at the market?" Wu Jun's words carried a sense of history.

Jiang Yuan said "Yeah" and added: "I saw a bloody handprint left on his leather jacket, so I'll compare it and see."

"Using fingerprints, that's okay." Wu Jun said, but still couldn't help but add: "This case is not easy to handle."

"Where was it stuck back then?" Jiang Yuan was also curious.

Wu Jun didn't answer, but instead asked: "What kind of nature do you think this case is?"

Jiang Yuan was mainly staring at the fingerprints, but he had also scanned the case roughly. He thought for a while and said: "Road robbery? Then escalated to murder?"

"Then why was it 8 meters away from the road? The scene photos specifically took a picture of the situation of the grass and trees by the road. Take a look, is it very lush? It's very inconvenient to walk over."

Jiang Yuan then flipped through the intranet photos, which were the photos of the cold case murder, and the transcription was relatively clear. It could be seen that the plants two or three meters away from the country road were very numerous. To walk 8 meters away, one couldn't walk directly; one had to squeeze in. If it were a knife threat, it would be easy to make mistakes.

Of course, the mistake part could also be the reason for the escalation?

Jiang Yuan didn't think it through too clearly, but understood Wu Jun's meaning and said: "So, you didn't think it was road robbery back then?"

Wu Jun shook his head instead and said: "I thought it was, many people thought it was. But the leader didn't recognize it."

"Why?"

"Because if road robbery led to murder, this case couldn't be solved." Wu Jun spread his hands and sighed again: "It makes sense. Back then, solving cases was still the three-axe method: one check, two arrange, three surprise. In this wilderness, turning it into robbery and murder made the case too difficult to handle."

The one check, two arrange, three surprise refers to scene investigation, queuing and investigation, and surprise interrogation.

This is a criminal investigation method established in a solid social relationship network.

The household registration system after the founding of the country made the mobility of the population greatly reduced. Most cases were committed by acquaintances, and a satisfactory case-solving rate could be obtained through investigation.

As for the wanderers outside, they were usually called blind flows by the police system, and they were checked, interrogated, and repatriated at every turn.

Precisely because of this, with the opening of social mobility, the working ability of the police system greatly declined, not to mention social security.

Wu Jun didn't tell Jiang Yuan one thing, and that was that if it were a road robbery case, there were still quite a few back then, and the leader's desire to solve the case wasn't that strong.

Jiang Yuan asked curiously: "What did Brigade Captain Huang say back then?"

"At that time, he happened to be the director of the police station." Wu Jun paused, recalled for a moment, and said: "It should be this case that changed the criminal police brigade captain."

Jiang Yuan couldn't help but want to gossip: "Was the previous brigade captain replaced because of this case?"

"Pretty much. There were quite a few unsolved cases in those few years."

Jiang Yuan saw that Wu Jun didn't mean to chat about this topic, so he continued with the case itself and said: "So, do you think the main problem with this case is the direction?"

"The deceased's relationship network was almost checked through, and there were no results." Wu Jun shook his head and said: "You should find the fingerprints well. Now it's all up to this to find something."

Random crimes were hard to check back then, and now they are even more impossible to check.

Over the years, the solved cold cases are actually mostly based on fingerprints and DNA, which is for similar reasons.

Many clues couldn't be checked back then, and after many years, they are even more impossible to check.

Jiang Yuan originally expected his master to provide more information. After all, many things are actually not written in the case files.

What Wu Jun just said, similar to the discarded investigation direction, belongs to things not in the case files.

It's just that it can't play any role for the time being.

Jiang Yuan didn't want to think about it anymore, turned back, and continued to process the fingerprints.

It was just like when he participated in the provincial fingerprint battle in Changyang.

At that time, there was no one to cooperate with you either; it was just purely checking fingerprints. If you check it, you have it; if you don't check it, you rest.

At that time, half of the provincial fingerprint experts, speaking of which, were all trace examiners at the LV3 level, who went home with a duck egg record.

Jiang Yuan processed one fingerprint until get off work time.

Wu Jun stood up on time and asked Jiang Yuan: "Get off work?"

"I'm working overtime." Jiang Yuan sighed, took out his phone, and sent a message to his father.

Wu Jun smiled and said: "Combine work and rest, rest for a while when you should."

"Interrupted the train of thought." Jiang Yuan shook his head helplessly.

During the provincial fingerprint battle, why were fingerprint experts more likely to achieve results? Importance is one aspect, but it's also because they can focus on looking at fingerprints without even having to go home.

Jiang Yuan didn't dare to take this bloody fingerprint lightly, returning to the state during the fingerprint battle, which was the most favorable. ===== CHAPTER 183 =====