Chapter 25: Crazy Scrubbing

Scrubbing the cup, scrubbing the glass, scrubbing the mirror, scrubbing the light, scrubbing the rough, scrubbing the thick, scrubbing the thin, scrubbing the soft, scrubbing the hard...

The work of investigation, from a large perspective, is colorful, but from a detailed perspective, it is all trivial matters.

Police all say that case solving is piled up by resources, which can be reflected during the scene investigation.

For example, scrubbing DNA and fingerprints, outsiders often think that as long as the criminal suspect leaves DNA or fingerprints at the scene, they will be found by the scene investigation personnel. But in fact, there is no advanced instrument in the world that can accurately find all fingerprints and DNA within a certain range.

Like fingerprints, first of all, they are divided into three types: dominant, plastic, and latent. The former two can be seen, the latter is self-explanatory, and requires certain means to be seen. And these means must also adopt different schemes according to the different materials of the fingerprint location. Or powder, or pipeline, or smoke, or chemical reagents, or different chemical reagents, or different chemical reagents...

In view of this, scene investigation or trace inspection personnel, to obtain a fingerprint, first need to judge where a fingerprint might exist, and then observe. The observation method can be done with the naked eye with the help of light or angle, or by breathing on a smooth surface to observe. It can also be observed using a magnifying glass or ultraviolet light. After determining the position of the fingerprint, it is then time to brush powder to extract the fingerprint, or use iodine fuming or silver nitrate or other reagents for chemical extraction.

Therefore, if a Spider-Man crawled over the ceiling, the person doing scene investigation would probably not find the fingerprints on the ceiling.

The trouble of DNA is even worse than fingerprints.

Fingerprints can be seen after all, DNA can be seen sometimes, and sometimes it can only be guessed.

Like common ones, extracting DNA from the victim's toothbrush, the police officer doing the extraction naturally cannot see anything, just guessing that there is a high probability of DNA on the toothbrush.

Changing to items with lower probability, such as shirts, bed sheets, and other close-fitting clothing, or water cups, porcelain bowls, and other items, whether there is DNA on them is entirely guessed.

The strength of the ability to do scene investigation is clearly reflected at this time. Some scene investigators think from the perspective of the criminal suspect, guessing the other party's actions, thereby finding possible traces, and orderly brushing powder; some scene investigators just pack shirts, bed sheets, and the like back in a brain, or just cut off a few pieces, regardless of whether it is really useful...

However, in general, the more people participating in the investigation, the stronger the ability, and the more time and energy invested, the higher the probability of discovering leads and evidence.

Jiang Yuan's operation method, in Wang Zhong's view, is extremely strong, but it is only during the homicide case that he feels it is relatively appropriate. Changing to a theft case, it is almost impossible to operate like Jiang Yuan. The cost of doing a tube of DNA, just the reagent is nearly 100 yuan, and the number of times it can be done in unit time is limited. It is very likely that the biological samples will grow hair before they are queued...

"We will scrub the bathroom again." Jiang Yuan processed the bedroom, and the sky was already dim.

Wang Zhong patted his head and pointed to a large box of evidence bags, saying, "Better come back tomorrow, these are already hundreds of copies, all given to the laboratory, they will go crazy."

Jiang Yuan explained: "More than half of them, it is estimated that DNA cannot be extracted, so reagents will not be used. The murderer cleaned the bedroom too cleanly. Look at the bedroom, many places where fingerprints were wiped clean. Coupled with the victim bleeding so much, the murderer must have spent a lot of time in the bathroom, rinsing rags, and even bathing and washing clothes are possible. The probability of mentioning DNA in the bathroom is very high."

"Little Hu and the others also guessed this, and they all scrubbed carefully." Wang Zhong said.

"Still too rough." Jiang Yuan paid attention to the operations of Little Hu and others when dealing with the corpse, and there was nothing to avoid at this time.

"Sigh... okay, I'll work overtime with you today." Wang Zhong didn't feel it before, but at this time, he also began to realize that the level of the scene investigators in the team was indeed a bit casual, just like his own fingerprint technology, the best evaluation is probably "usable."

And in the few hours that just passed, the fingerprints Jiang Yuan found, although not necessarily able to solve the case, have already proved that his and Old Yan's "usability" is insufficient.

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

"Sign your name and go back." Wang Zhong didn't expect the elderly to stay for long. Witnesses are like this, either they don't want to get involved at all, or they walk around and talk nonsense, or they don't have patience.

Wang Zhong didn't have the idea of educating others, directly took the scene investigation record, turned to the signature page, let the two write their names, opened the door and let them out, only exhorting: "What you see and hear today, you can only say when the court or relevant departments ask, and you cannot leak it at ordinary times, otherwise you will bear criminal responsibility."

The two old men went out, nodding impatiently and saying "know, know."

Wang Zhong nodded habitually, closed the door and returned to the room, continuing to help Jiang Yuan scrub DNA and fingerprints.

The lighting in the bathroom is poor, and it is even more laborious to scrub.

Jiang Yuan, however, scrubbed very energetically.

The Shou Xiankan LV4 acquired not only improved his operational ability, but also included his cognitive level.

And various criminal theories actually explain a truth: the longer the criminal stays at the crime scene, the more things they do, the more flaws they will reveal.

Like the murderer this time, he seemed to have cleaned the crime scene carefully, and even calmly took a bath, but in Jiang Yuan's understanding, this only reflected the amateur and arrogance of the murderer.

Current DNA technology can even identify identity information from sweat. The delusion of cleaning the bathroom to perfection in a very short time is absolutely impossible. If he were a little more professional, he should have wrapped the bathroom in plastic, and then directly taken away the plastic, buried or burned it, and the leaked physical evidence information would be much less.

However, in that case, there would be traces of tape or stickiness at the scene...

Jiang Yuan was not sure which place could scrub the murderer's DNA. He was just young, had good physical strength, and scrubbed crazily.

Scrub.

Scrub, scrub...

Jiang Yuan was still in the excitement period of a newcomer. Having just acquired the Shou Xiankan LV4 skill, the scene he had truly investigated was just this one. Naturally, he tried and practiced to his heart's content.

In the skills of scene investigation, technique is certainly very important, meticulousness is indispensable, and on the other hand, abilities such as physical strength, energy, and concentration are the key to going to the next level. This is like Xue Huaiyi losing favor with Empress Wu because his experience was rich and his technique improved, so he was disliked? Obviously not. The same truth, the Zhang brothers would not lose favor because they were young, reckless, bloated, and impulsive.

Of the above, Wang Zhong was not lacking a little bit. However, although he was a bit tired, he was driven by Jiang Yuan and supported him with all his might.

Jiang Yuan especially carefully scrubbed the ceiling and corners of the bathroom.

The further back, the more careful and confident he became.

This room was not dry-wet separated, but the area of the bathroom was small, and the probability of water droplets splashing on the walls and ceiling when bathing was not low, and it was impossible to clean thoroughly in a short time. The only problem was whether DNA could be scrubbed. Bloodstains were likely to be washed away or destroyed, but wanting to wash away all DNA traces, this person was mostly a layman.

Ordinary people, unplanned murder, normally will not learn relevant skills in advance. Even if they learn, they may not be diligent and serious, and they may not be proficient. Then it is reasonable to have a high probability of being dug out by police who are diligent, serious, and proficient.

Night fell.

Jiang Yuan and Wang Zhong dragged large and small bags, returned to the police station, and went straight to the DNA laboratory.

Nowadays, cases using DNA to solve crimes directly are increasing, and the police bureau's investment in DNA laboratories is increasing day by day. Even in the poor county of Ningtai, under the guidance of various subsidies and policies, a DNA laboratory was built according to the standards given by the ministries and commissions.

This is also the gold-swallowing beast unit of the police bureau. The laboratory with a total of three people swallows more than 10% of the police bureau's funding every year, and it has to increase from time to time.

However, contrary to Wang Zhong's expectations, the DNA laboratory just silently accepted the pile of evidence bags and did not raise any objections.

They didn't even carefully check and pick on the biological samples sent by Jiang Yuan and Wang Zhong.

"Old Qian of DNA, how did he become so easy to talk to." Wang Zhong went straight to the forensic office with Jiang Yuan and muttered.

In the forensic office, Wu Jun also didn't go home. Like most criminal police, he sat in the office, organizing the materials done during the day. Standing up and rubbing his eyes, Wu Jun said slowly: "In the afternoon, the Brigade Captain was still losing his temper. Now the problem is that there are no leads. The DNA laboratory wishes you would send samples over, so as not to have nothing to do."

Jiang Yuan laughed: "Is it considered having nothing to do if you don't work at night?"

"The Brigade Captain didn't go home either." Wu Jun said: "If you don't detect anything, they will have to re-examine themselves."

Wang Zhong looked at Jiang Yuan and clicked his tongue twice, saying: "They would be white even if they went. With their level of scene investigation, it's not that I'm saying, ordinary cases are fine..."

Wu Jun interrupted Wang Zhong: "Do you think they don't know it themselves?"

"Uh..." Wang Zhong was speechless and returned to his office silently.

Jiang Yuan was quite satisfied, packed up, and spread out a folding bed directly in the office.

Until the noisy sound woke up the police officers who had stayed up all night.

"DNA matched a person, Team Leader Liu took people there." Wang Zhong rushed into the office first, with secretions hanging from the corners of his eyes. ===== CHAPTER 26 =====