Chapter 533 of the main text, the technical person in charge of footprint analysis continues to report.

On the projection, there are three sets of shoe prints that have been separated.

"After comparing, it can be determined that two of the groups belong to the victim Li Yansong's taxi drivers."

The two sets of shoe prints on the projection disappeared, leaving only a set of shoe prints on the left.

"The shoe prints on the foot pads are extracted in sequence. We used existing technology to extract seven levels of shoe prints on the foot pads."

"After the separation, six-fold shoe prints were successfully extracted."

"The first of the shoe prints in the first four levels is from the day shift driver Chen Qiang, and the second level is from the victim Li Yansong."

"The third level is Chen Qiang's, the fourth level is Li Yansong's, but the fifth level is this set of strange footprints, and the sixth level is Li Yansong's."

"The sixth shoe print can be confirmed to be the last set of shoe prints left after Li Yansong was killed."

"Then push back, the fifth level is the unfamiliar shoe print, which should be the shoe print left by the murderer after driving for a short time!"

Chen Yan and Wang Fenglei stared at the shoe prints on the projection, looking a little excited.

So far, this is the only evidence left by the murderer.

"Compare it in the information base of the ex-confidential personnel right now!"

"yes!"

The fingerprint was not found, but the shoe prints were finally not disappointing.

Moreover, for Chen Yan, this set of shoe prints is not just a simple set of comparison data.

With systematic rewards, Chen Yan’s understanding of shoe printing is beyond the reach of his ability.

In Chen Yan's past life, there was actually a specialized professional police type in the police station, which is a footprint analyst.

There are very few such talents, but each one is very powerful and precious.

General footprint analysts can judge the footprint owner's weight, walking habits and other basic information based on the footprint.

Some of the stakes are able to judge not only these basic information, but also know the murderer's profession characteristics, determine gender, height, age and other information.

This will be of great help to solve the case.

Chen Yan's traces are firm in his skills, and he has a knowledge reserve in this area.

"Battle Wang, help me arrange a room and be quiet. I want to conduct footprint identification and analysis on this set of footprints."

Footprint identification and analysis?

Wang Fenglei was slightly stunned: "Chen Yan, do you still understand this?"

"I know a little bit, in this way, Brigade Wang, our provincial brigade should have talents in this area. You can ask the other side to do an appraisal together."

"This way, I will integrate it with my appraisal and I will probably get more information."

The Liao Provincial Investigation Brigade naturally has talents in this field, but it is hard to say what level it can be achieved.

Especially, the footprint marks that are not very clear and peeled off by multiple footprints are difficult to determine.

Furthermore, the murderer's footprints were left in the sitting position, and a lot of information analysis and judgment will not be accurate.

For example, the simplest weight.

The shoe prints left in the sitting position and the shoe prints left in the standing position are completely different.

On the other hand, this has something to do with the shoes you wear.

But since Chen Yan said that, it means he must be sure.

"Okay, I'll make arrangements now!"

Chen Yan nodded.

Chen Yan is more clear about the difficulty of footprint analysis than Wang Fenglei.

But there are no other clues except this.

The fingerprints were not left, the soil analysis results have not been released, and the video investigation has not been found.

Now, there is only this set of footprints.

Ten minutes later, Chen Yan had already sat in a quiet office.

On the desktop are more than a dozen photos of footprints from different angles.

Front, side, front and back, etc.

However, not every photo is very clear.

Some angles even have only half a photo.

The photos here are all restored based on the actual size of the shoe prints in equal proportions. Chen Yan is now using a ruler to measure them.

Generally speaking, it is easy for everyone to judge the owner's weight by footprints.

footprint

The deeper you are, the bigger the weight is.

The footprints are shallow and the weight is definitely lighter.

In fact, in the real analysis of footprints, the depth of footprints is not very important.

Because on different grounds, even for the same person, the depth of footprints left by the same person is different. In the trace analysis, the most important footprint size is the most important footprint size.

The clarity of footprints in different parts. Use these to judge the basic information.

For example, the clarity of footprints at the arch of the foot.

Under the same conditions, the shallower the footprints at the arch of the foot, indicating that the owner's arch is relatively high.

In most cases, excluding interference from diseases such as flat feet, the height of the foot arch can determine the proportional relationship between weight and height.

The size of the footprints at the arch part can determine the size of the arch bone.

Through these, the owner's height range and weight range can be calculated.

This is the principle of footprint analysis.

This is also why Chen Yan kept using a ruler to measure data in different directions of footprints.

Time passes by bit by bit.

Each group is advancing their respective work.

There are the largest number of people on Liu Qingshan side.

More than 300 detectives were scattered in the self-built building area of ​​Phoenix Street, looking for cameras from door to door.

Although there are only two alleys entering the alleys of the self-built house area from the surveillance camera No. 36 on Phoenix Street to the surveillance camera No. 37 on Phoenix Street, no one can guarantee that the taxi will drive in this area after entering the alley.

Therefore, the entire self-built housing area of ​​Fenghuangshan Street must be included in the survey scope.

There are more than 17,000 residents here.

There were quite a few people listening to three hundred people. On average, each detective had to investigate about fifty households before they could all be investigated.

Of course, more than 17,000 households were not investigated in place. The detectives only focused on checking residents with cameras outside the house.

After one night, I found out the basic situation.

3298 households!

In the entire area, 3,298 households have installed various cameras.

Among them, there are fewer people who can transfer their homes.

The main reason is that there are more shops along the street in the self-built house area.

About 80% of them are shop-mounted cameras.

At noon the next day of the incident, all the detectives copied the video materials they searched.

But, the next step is the most troublesome job.

That's watching videos.

Video information between 3:08 and 4:30 yesterday.

3298 households, one and a half hours of video.

The total length of videos is more than 3,000 hours.

Liu Qingshan asked the Shen City Detective Team to apply for the right to use the Expo Center.

More than 300 people gathered here to watch the video.

The reason for concentration is to increase everyone's attention.

If you look at it separately, there is no atmosphere and it is easy to miss important information.

The most important thing may be the flash of a second in the surveillance.

There are more than 300 people, each of whom is assigned ten videos.

Read all of them and the results will take ten and a half hours to come out. At this time, there are two urgently needed materials.

instant noodles and eye drops.

After yesterday's case analysis meeting, these people were scattered and have not had enough food yet.

Of course, you can't work on hunger, eat first before talking about it.
To be continued...