Chapter 1030

"This area should be the area that Xu Li might have come into contact with. Area No. 2." Deputy squad leader Qi Yongmiao pointed out the designated area to Jiang Yuan with slight nervousness.

Jiang Yuan had previously obtained the fingerprint of the middle finger of the corpse through the deep-frying method from Corpse No. 1. Now, if a matching fingerprint can be obtained from a certain area in the supermarket, it can definitively prove that Xu Li is the deceased.

A more definitive way is to obtain the same DNA, because although Corpse No. 1 has a high degree of decay, DNA was still obtained. But because Xu Li is an orphan and the rented room has already been rented to other tenants, although the investigation personnel also tried to extract DNA, this kind of comparison is actually more troublesome.

In contrast, Xu Li, as a stocker, is easily able to leave fingerprints in the supermarket.

While waiting for Jiang Yuan, Wu Junhao and the others had already roughly delineated the area that Xu Li might have come into contact with through the store's surveillance. However, no matching fingerprint was obtained in the delineated Area No. 1.

Qi Yongmiao held his breath at that time.

If it weren't for Jiang Yuan taking the fingerprints himself, Qi Yongmiao would have called someone to take them again.

Jiang Yuan still looked calm. He also attaches great importance to this matter, so he came over specifically to take the fingerprints himself. Liu Jinghui and others who accompanied him were observing this small supermarket and had already started thinking, taking Xu Li as the victim.

Area No. 2 is a shelf in the warehouse, located relatively far back. From the surveillance, although others have come into contact with this place after Xu Li, the frequency is not high, the number of times is not many, and the point is that there is no wiping behavior, which is more conducive to preserving fingerprints.

Jiang Yuan took a gray squirrel hair brush, selected silver powder for the fingerprint powder, and then brushed it carefully on the black-background shelf, and the fingerprints in patches were revealed instantly.

Jiang Yuan looked at these fingerprints carefully again and only chose the middle finger fingerprint to extract.

Extracting others is useless; Corpse No. 1 only extracted a fingerprint of the middle finger of the right hand.

No suitable fingerprint was found in the area just collected. Jiang Yuan's guess is that Xu Li did not leave the fingerprint of the middle finger of the right hand in that area, or left it and was accidentally wiped by someone else. Therefore, although it did not match, he was not too anxious.

Those who do fingerprints have had too many similar experiences—confident fingerprints that did not match can be said to be a situation that every trace examiner has had. After doing similar work for a few years, the mentality will be more stable. Or more broken.

From another perspective, the suspect or victim confirmed by the criminal police with full confidence may not really be the suspect or victim. Fingerprint and DNA technology not only caught many criminals but also truly saved many innocent people.

Many times, the world will have coincidences, and things that do not conform to reasoning will appear. This situation is not many, but once it appears, often only the purest technology can drag it out of the quagmire.

Jiang Yuan now wants to use technology to determine that Xu Li is Victim No. 1. Although it is said that including Jiang Yuan himself, he has basically believed that Xu Li is, there is still a chasm between belief and evidence.

It should also have such a chasm.

Jiang Yuan collects fingerprints on-site, and compares one as he collects one.

This kind of comparison does not need the participation of computer software and tends more to the early fingerprint comparison mode. It is a one-to-one comparison of the similarities and differences between two fingerprints. It is equivalent to the final confirmation step after the software produces candidate fingerprints.

Jiang Yuan does not even need to mark feature points; the fingerprints of the original corpse have long been remembered by him, and now it depends on whether the newly taken fingerprints match.

In this way, the progress of the comparison is also very fast. After taking six or seven fingerprints, one fingerprint was left by Jiang Yuan.

This fingerprint looks slightly different from the original corpse's fingerprint at first glance, but those familiar with fingerprints know that fingerprints left on objects are not immutable.

Because the pressure when the finger touches the object is different, the fingerprint, that is, the pattern on the finger, will spread out due to high pressure and concentrate due to low pressure, and will also be a partial fingerprint due to the different tilt angle of the contact surface.

If there is a living person present, rolling a full fingerprint out is easier to compare. Now that the person is dead, it is equivalent to two partial fingerprints being compared. If you don't want to miss anything, you have to have an LV2 fingerprint level.

Jiang Yuan is naturally fully covered.

The LV6 fingerprint analysis method, used in this kind of place, is like an island keeper who has worked for a year returning home to see his young wife.

Jiang Yuan spent a slightly longer time studying the fingerprint in front of him, but it was only to confirm it.

A few minutes later, Jiang Yuan straightened his waist, did not take any more fingerprints, nodded and said: "Confirmed identical, it is indeed Xu Li's fingerprint."

The police officers present were all excited.

This is not just a question of determining the identity of Victim No. 1, but also opened a huge breakthrough for the case.

Liu Jinghui immediately said: "I will contact the technical investigation first to see if I can find some clues from the mobile phone number."

Since the murderer used his mobile phone to send messages and so on after Xu Li died, it means that the murderer was exposed at that time.

And many of the technical investigation's technologies are very difficult to guard against in daily life.

Even if the murderer knows how to guard against it, he has to pay a price, or rather, in order to guard against these things, the murderer needs to make certain compromises, and his actions may also be deformed.

Liu Jinghui does not need to consider how many possibilities there are in this; anyway, check it first.

Jiang Yuan naturally agreed.

The murderer borrowed the deceased Xu Li's mobile phone to send messages, which itself is a very important clue.

Liu Jinghui arranged for people to collect the surveillance videos of nearby shops and property, and then pulled Jiang Yuan to the side, whispering: "The murderer is painstaking and must have carefully designed this murder. Xu Li disappeared the day after he got his salary. It is hard to say that this is an isolated event. However, the murderer was also exposed because of this."

"What do you mean?"

"The murderer is likely an acquaintance of Xu Li, at least has a channel to understand him. Therefore, murdering Xu Li is not random killing." Liu Jinghui sighed and said with bright eyes: "He thought this could reduce the possibility of being discovered, but also aggravated the connection with the victim."

"Xu Li is an orphan." Jiang Yuan said the situation known here and said slowly: "He is a supermarket stocker, and the people he contacts daily should not be too many."

"Considering from the murderer's perspective, the point of being an orphan might also be necessary." Liu Jinghui's train of thought became clearer and clearer, saying: "The murderer seems to be killing three people in a row, but his plan might have been done a long time ago. And if he wants to kill people in a row, he needs the first person, the second person to be discovered as late as possible, and from his planning, if the victim has family members, once the case is reported, Xu Li enters the missing person database, and the probability of being discovered by us is much greater."

Jiang Yuan nodded noncommittally.

Liu Jinghui continued: "Also considering from the murderer's perspective, he knows so much about Xu Li, but he will not be someone Xu Li is too familiar with, otherwise it is too easy to be investigated. Therefore, the murderer is likely not a strong contact person of Xu Li."

Jiang Yuan nodded and said: "A chance encounter, knowing a little."

"Especially knowing the time he gets paid." Liu Jinghui licked his lips and whispered: "This means the murderer likely had communication with Xu Li in the last two months, online or offline."

"En."

"Then I have an idea."

"Oh?"

Liu Jinghui said: "Xu Li, as a supermarket stocker, I think the number of people he can contact must be limited, and to understand him, it takes a period of time. I think we can do a screening. Any mobile phone that is in the same location as Xu Li at the same time, if the duration exceeds 3 minutes, it will be listed as a suspect to see how many suspects can be gathered."