On The Day Of My 100th Blind Date, I Arrested My Date

Can you use your brain?

Qin Yu, who was laughing, looked at Chen Yan as if he were looking at a fool.

However, Chen Yan was unmoved and just looked at Qin Yu who was laughing wildly.

Yes, Qin Yu's laughter stopped in the summer, just like a crowing rooster being pinched by the neck. The interrogation room suddenly became eerily quiet, and it was as if a pin drop could stop it.

Only Qin Yu's eyes met Chen Yan's.

"Are you scared?"

The corners of Chen Yan's mouth turned up slightly, "You did wear gloves when you climbed the escalator, so you didn't leave any fingerprints, but you did not clean up the shoe prints on the escalator cross arms, right?"

Qin Yu was silent. He didn't believe that his footprints could be left on the crossbar, which was only as thick as his thumb. Even if his eyes were left, could a shoe print be used as evidence to lock him? "Captain Chen, after Wang Xu was killed, I have always been the object of your suspicion. Indeed, the two renovation projects I took on in Hengchang Community were just to deal with Wang Xu. I even secretly allocated a house to their family. Door key.

"But Captain Chen, your investigation of the incident is very clear. I did not commit any crime against Wang Xu."

"Wang Xu was killed, and you found a way for the murderer to avoid surveillance, which is the underground pipe network, but what does this have to do with me?"

"Although I'm not a policeman, I still know some common sense. Let's not talk about whether I can leave footprints on the iron ladder crossbar that is only as thick as my thumb. Even if I leave footprints, what will happen?" "Such a small footprint. A cross-sectional area of ​​a shoe sole may not leave a complete pattern, right? ""I know that even if different people wear the same pair of shoes, the footprints left will never be the same, but Captain Chen, you rely on such a small Does the incomplete shoe print mean it was me who committed the murder?

"of course not."

Chen Yan glanced at Wang Gang beside him. Wang Gang took out a stack of photos from the file box and threw them in front of Qin Yu.

"Qin Yu, first of all, you neglected to leave footprints on the iron ladder crossbar. You may have considered this and even used a broom to clean the iron ladder crossbar. However, the iron ladder crossbar has It’s not the same as dust on the ground.”

"The footprints left on the ground with residual dust are clear and easy to remove, but the footprints on the iron cross arm are not clear and are more difficult to remove due to the material. Just sweeping with a broom is not enough. You have to rub it with a rag to remove it. Qian Jing.”

"Although the traces are very shallow, the shoe prints can still be extracted under the illumination of fluorescent lights."

In fact, this situation has a certain degree of coincidence, which is related to the humidity of the air.

Because it had just rained in the city before the incident, and because there was no sunlight all year round, the humidity in the underground pipe network was naturally high.

The surface of metal will undergo some corrosive changes in this environment. When exposed to external force, it will deform and produce changes that are difficult to recover. Although this change is very slight, it can still be observed.

In addition, because there is dust on the soles of Qin Yu's shoes, the dust will also remain on the iron ladder cross arms. Although no traces can be seen on the surface after being cleaned with a broom, this is just the dust covering up the shoe prints.

Qin Yu frowned and listened to Chen Yan's explanation. He didn't say anything for a long time. He just stared at the photo in front of him, motionless, as if he were a statue of wood.

"The second question is about the size of the shoe print you mentioned. This is indeed a problem."

"After all, the cross-sectional area of ​​the iron ladder is very small, and even if there is only one shoe mark left, it will be irregular."

"but…."

Chen Yan looked at Qin Yu, who was silent, and pointed at the photo in front of him, "You left a total of 24 shoe prints on these iron ladder cross arms, with your left and right hands alternating. Every time you step on them, The positions of the upper cross arms are different, so that when all the footprints are superimposed, a large-area footprint model can be obtained. "

"Qin Yu, the last two photos in front of you are the puzzle shapes of your left and right feet." Qin Yu subconsciously took out the last two photos. As expected, they are the spliced ​​shoe prints of the left and right feet. The left and right feet are both the middle part of the sole. There is no Toes and heels.

Looking at the two photos, Qin Yu said nothing.

Chen Yan didn't urge him, he just looked at Qin Yu who was sitting quietly opposite.

a long time.

call!

Qin Yu exhaled a breath of turbid air and let out a long sigh.

Before killing Wang Xu, Qin Yu checked the identification methods of fingerprints and shoe prints. It does not mean that all fingerprints and shoe prints can be used as criminal evidence for identification.

In the past, complete fingerprints or complete shoe prints were required to be used as evidence of crime to charge criminal suspects.

Because technology was not yet developed at that time, both fingerprint comparison and shoe print identification needed to be of high integrity before they could be used as evidence for prosecution.

But now with the development of technology, the requirements for the integrity of fingerprints or shoe prints are also constantly decreasing.

Especially for fingerprints, there is no need for complete fingerprints at all now. Some technical masters can use half a fingerprint or a smaller area to complete the comparison.

Because not only the entire fingerprint is different for each person, but even the spacing of the fine textures of any fingerprint is different, it is just a difference in degree.

The same is true for shoe prints. Current criminal evidence charges only require more than one-third to be used as a distinguishing standard, and even the area required for the sole of the foot can be even smaller.

The two photos Qin Yu held in his hand had already depicted the entire soles of his feet.

For Qin Yu, the proof is now irrefutable and there is no point in struggling anymore.

However, Qin Yu looked at Chen Yan with a sharp look, "I don't accept it!"

yes!

Qin Yu refused to accept it!

It's not that he didn't think of this, as Chen Yan said, he also used a broom to clean the footprints on the iron ladder crossbar, and it was confirmed by him at the time.

He did not lose on carelessness, but on expertise.

"Captain Chen, I am just a decorator. If I beat the police, I will never leave this flaw. You will never be able to catch me."

Facing Qin Yu's words, Chen Yan was indeed deeply touched.

When it was discovered that the murderer had escaped surveillance through the underground pipe network, Chen Yan was extremely excited.

The underground pipe network is such a small place, Chen Yan believes that the murderer will definitely leave many clues and evidence.

Chen Yan even felt that if he was the murderer, he would never have thought that the police could guess that he was hiding from the camera through the underground pipe network.

This can be said to be foolproof.

The result was just as Chen Yan expected, the murderer did leave many traces in the underground pipe network, such as blood drops, brooms and murder weapons.

The case is hopefully solved!