Chapter: 44

Therefore, if a spider-man really climbed over the ceiling, there is a high probability that the person doing the on-site survey will not find the fingerprints on the ceiling.

DNA is as much trouble as fingerprints.

After all, fingerprints can be seen. DNA can be seen sometimes, but sometimes it can only be guessed.

It is common to extract DNA from the victim's toothbrush. Of course, the police who do the extraction can't see anything. They just guess that there is a high probability of DNA on the toothbrush.

Switching to items with less high probability, such as shirts, bed sheets and other underwear, or water glasses, porcelain bowls and other items, whether there is DNA on them is completely guesswork.

The ability to do field surveys is clearly reflected at this time. Some surveys think from the perspective of a criminal suspect, guessing the other party's actions, so as to find possible clues, and paint in an orderly manner; Pack it up, or just cut out a few pieces, regardless of whether it is really useful...

However, in general, the more people involved in the investigation, the more capable they are, and the more time and energy they invest, the higher the probability of finding clues and evidence.

In Wang Zhong's opinion, Jiang Yuan's operation method is very strong, but he thinks it is more appropriate during the murder case. If it is a theft case, it is almost impossible to operate like Jiang Yuan's. The cost of making a tube of DNA is 100 yuan less for reagents alone, and the number of times that can be done per unit time is even more limited.

"Let's clean the bathroom again." Jiang Yuan cleaned up the bedroom, and the sky was already dark.

Wang Zhongting patted his head, pointed to a large box of evidence bags, and said: "Why don't you come back tomorrow, there are hundreds of copies of these, and give them all to the laboratory, they will all go crazy."

Jiang Yuan explained: "There are more than half of them. It is estimated that no DNA can be mentioned, and no reagents will be used. The murderer made it too clean. Look in the bedroom, the fingerprints in many places have been wiped clean. Then In addition to the fact that the victim bleeds so much, the murderer must have spent a lot of time in the bathroom, washing rags, maybe even taking a shower and washing clothes. The probability of DNA being mentioned in the bathroom is very high."

"Xiao Hu and the others also guessed the same way, and they all checked carefully." Wang Zhong said.

"The rubbing is still too rough." When Jiang Yuan was dealing with the corpse, he had paid attention to the operations of Xiao Hu and others, so he didn't have anything to taboo at this time.

"Oh... well, I will accompany you to work overtime today." Wang Zhong didn't think so before, but now he also began to realize that the level of the few surveyors in the team is indeed a bit random, just like doing fingerprints by himself. Like technology, the best evaluation is probably "usable".

And in the past few hours, those missing fingerprints that Jiang Yuan found may not be able to solve the case, but it has proved that he and Lao Yan's "useability" is insufficient.

"That..." The old man at the door couldn't stay still, and said, "We have to go home for dinner."

"Just sign and go back." Wang Zhong actually didn't expect the old man to stay for long. Witnesses are all like this, either they simply don’t want to get involved, or they just walk around and talk, or they just have no patience.

Wang Zhong also had no intention of educating others, so he directly took the on-site inspection transcripts, turned to the signed page, asked the two to write their names, opened the door and let them out, only telling: "What you saw and heard today, It can only be said when asked by the court or relevant departments, and it cannot be leaked out at ordinary times, otherwise it will bear criminal responsibility."

When the two old men went out, they nodded impatiently and said, "I know."

Wang Zhong nodded as usual, closed the door and went back to the house, continuing to help Jiang Yuan wipe DNA and fingerprints.

The lighting in the bathroom is not good, and it is more difficult to wipe.

Jiang Yuan rubbed very hard.

Crime scene investigation LV4 not only improves his operational ability, but also his cognitive level.

And all kinds of crime theories actually explain a truth, the longer the criminal stays at the crime scene, the more things he does, the more flaws he exposes.

Like the murderer this time, he seemed to have cleaned up the crime scene carefully, and even took a bath for himself calmly, but as far as Jiang Yuan understood, this only showed the murderer's amateurism and arrogance.

The current DNA technology can even identify identity information from sweat. It is absolutely impossible to clean the bathroom to a flawless state in a short period of time. If it is really a little more professional, at least the bathroom should be covered with plastic, and the plastic will be taken away, buried or incinerated, and the leaked physical evidence will be much less.

However, in that case, there will be marks of tape or sticky on the site...

In fact, Jiang Yuan is not sure where the murderer's DNA can be wiped. He is young, physically strong, and crazy.

wipe.

Wipe...