This case of the TZ City Criminal Investigation Detachment can be said to be quite a failure.

The real murderer was not found, and the innocent people who were wronged committed suicide in the detention center.

Lu Chuan can even think now of how frightened he should be when the criminal police of the TZ City Criminal Investigation Detachment saw the photos sent by the restaurant owner.

There are also five blood characters left by the deceased on the wall of the detention center.

I was wronged!

Even if Lu Chuan was not at the scene, he could imagine how helpless and sad these words should be.

"What do they want us to do?"

Liu Guodong sighed deeply.

The TZ City Criminal Investigation Detachment has handled the case to this extent, and now it has sent it to ask for help, and there must have been something to discover, but it can't be done by itself.

"Blood fingerprints."

Qin Yong pulled out the blood-colored fingerprints found on the murder weapon in the file.

"The most important evidence for the TZ City Criminal Investigation Detachment to lock down the suspect is this bloody fingerprint."

Lu Chuan nodded, in general criminal cases, fingerprints are the most important evidence of a crime.

Any fingerprints that appear at the scene of the crime are the most important evidence that must be paid attention to in the current investigation.

What's more, this fingerprint was found on the murder weapon.

In fact, most crime scenes are not all fingerprints.

In terms of probability, the proportion of criminal cases that can be solved through fingerprints is only about 20%, or even lower.

For example, the number of criminal cases involved in the fingerprint battle organized by the provincial department is not particularly large.

In addition, fingerprint extraction also has effective and ineffective claims.

Fingerprints were collected at some scenes, but there were no murderers.

At some scenes, even if the murderer left fingerprints, they may not be able to collect them.

Lu Chuan's fingerprint collection skills are specifically for fingerprint collection.

"Because of the existence of this fingerprint, the police who handled the case at that time directly locked up the so-called suspect who committed suicide in the detention center."

"Ignored some alibi from the other party."

This is described in the dossier.

The innocent man was in the restaurant where he was eating, although there were no surveillance cameras, and the boss was not impressed with the deceased at the time.

But there are cameras around the restaurant.

Yesterday, the TZ City Criminal Investigation Detachment extracted a video of an innocent suicide person passing by during the time period of the crime in the surveillance at the entrance of a camera building more than 200 meters away from the restaurant.

It further corroborates the photographic evidence brought by the restaurant owner.

"After figuring things out, they did a more detailed analysis of the fingerprints, and they found this."

Qin Yong pulled out another piece of printer paper.

"There seems to be another layer of fingerprints on top of it."

The lines on the printing paper are still blood fingerprints, almost exactly the same as the previous picture.

But with Lu Chuan's ability, in fact, when he first saw this picture, he knew that they were really mistaken.

"Someone used a fingerprint sleeve to simulate the fingerprints of an innocent person."

Qin Yong was not surprised that Lu Chuan could find this.

"Yes, the Taizhou Criminal Investigation Detachment sent the fingerprints to the Technical Appraisal Center of the Provincial Department yesterday afternoon, but they were not successfully extracted there."

"The suggestion from the provincial department is for you to help take a look."

"Are you sure?"

Lu Chuan frowned.

This type of superimposed fingerprint is not uncommon.

In the vast majority of crime scenes, superimposed fingerprints will appear.

In fact, there are certain methods and skills to do this kind of fingerprint separation.

The fingerprint identification experts of the provincial department, such as Tian Rong and Lu Chuan, were also familiar with it when they participated in the fingerprint battle last time.

It stands to reason that superimposed fingerprints will not be too difficult to identify and analyze in the hands of experts of Tian Rong's level.

The reason why this fingerprint was not done by the provincial department was only

One reason.

The superimposed fingerprints are too light.

When the murderer committed the crime, he should have brought something like a fingerprint mold glove or something.

The fingerprints left on the murder weapon were those of the innocent suicide, while the fingerprints of the real murderer were imprinted on the mold by pressure.

Due to the uneven texture of the fingerprint, the imbalance of mold pressure is caused.

So there is a layer of fingerprints as delicate as a spider's web, covering the blood fingerprints.

What Lu Chuan has to do now is to separate the cobweb-like fingerprints from the blood fingerprints.

Comparisons are then made within the system.

"I haven't done this type of fingerprint analysis before, so I'll take it back and try it."

"Okay, if it is successful, there is no way to do it, after all, the experts from the provincial department have not succeeded in appraisal."

Qin Yong actually didn't have any pressure.

Since the TZ City Criminal Investigation Detachment has found it, there is naturally no reason not to help.

However, whether it can be done or not, no one can pack a ticket.

Survey Office.

Lu Chuan was staring at the computer in a daze.

Generally, superimposed fingerprints can be processed by image layering.

But the premise is that the superimposed fingerprints are relatively clear, or the depth of the traces is similar.

But now this fingerprint is obviously not good.

The fingerprints of the real murderer, because of the fingerprint mold gloves, the indentations left are very inconspicuous.

Paint software can't even recognize the presence of superimposed fingerprints at all.

The general graph number transformation, using the method of data rubbing, Lu Chuan has just tried it.

The data flow of blood fingerprints is too large compared to spider-like covering fingerprints, and it is difficult to do data stripping, let alone enhancement.

"How's it going, not easy?"

Lao Bai handed Lu Chuan a cigarette.

In the past, when Lu Chuan did fingerprint identification, it was basically a screen of data streams, and the results could be obtained in ten minutes, half an hour, or at most one or two hours.

Although Lao Bai can't understand the whole process, he can clearly feel a taste of ease.

This time it was different, Lu Chuan looked at the fingerprints on the computer screen in a daze for half an hour, but he never started to operate.

Taking the cigarette, Lu Chuan nodded.

"The superimposed fingerprints are too shallow, and there is no way to extract them by ordinary methods, so I have to study them."

"Take your time, but if you can't do it, I guess no one in our province will be able to do it."

After Lu Chuan participated in the fingerprint battle organized by the provincial department last time, he already faintly had the title of the first person in the province to identify and analyze fingerprints.

Recently, many other city criminal investigation detachments have also come to help.

The mathematical transformation did not work, and the image layering that came with the software could not be recognized, so Lu Chuan studied for a long time and decided that he could only program it by himself.

In fact, the most important thing for the separation and extraction of superimposed fingerprints is to layer the image.

And the method adopted by Lu Chuan is more complicated.

The blood fingerprint on the bottom layer is dark in color and has heavy lines, and the covering fingerprint on the top is light in color and thin in line.

In this case, the gray value of each fingerprint ridge is very different.

The gray values of the blood fingerprint and the covering fingerprint are in the range of two ranges.

Theoretically, as long as Lu Chuan can distinguish the gray value of the image, and then extract the image with different gray value areas, he can separate two superimposed fingerprints.