Attending ex-girlfriend's wedding, arresting the groom's officer on the spot

Only by obtaining the DNA information material can the DNA information be stripped and identified, and then compared with the murderer's DNA, so as to identify the other party as the real murderer.

This is the current criminal investigation technology, that is, the evidence recognized by the court when conducting a public prosecution.

The so-called ironclad evidence requires this step.

Yang Lin continued on the phone.

"I have isolated three different types of cells from the mop. They should belong to three different people. Based on current speculation, one of them should be Wang Lili, another is Wang Hong, and the other one is most likely the murderer."

There are three types of cells isolated from the mop handle, which is relatively common and consistent with the current situation known by the police.

However, only one type of cell material was separated from the handle of the kitchen knife, and the parts of Wang Lili and Wang Hong were not separated.

From this point of view, there should be no problem. After all, Wang Lili should not have come into contact with the kitchen knife over there.

Wang Hong hadn't used it for a long time. In his memory, the kitchen knife had been idle for a long time after he bought it. It was only used once during the Chinese New Year to chop bones.

When Wang Hong took the kitchen knife from the refrigerator, she just pinched the handle with her fingers, leaving clear fingerprints on it.

As for the part with fingerprints, Yang Lin conducted fingerprint identification analysis, so the cells in this part were not extracted.

In this case, there should be only one type of cells extracted from the handle of the kitchen knife, which is logically correct.

"Based on the labeling, the third type of cells found on the mop handle and the cells found on the kitchen knife handle should be the same. I then enhanced the DNA information of both types of cells."

This step is a critical step. Only when this step is completed can DNA information be collected. If this step fails, the above editing may be wasted. This step is very important in trace evidence analysis.

This is the DNA amplification often done by Yang Lin, Lu Chuan and others.

Generally speaking, the substances collected in trace evidence analysis are very subtle, and some may only be measured in milligrams.

Therefore, it is obviously very difficult to extract relevant information about the suspect, especially the DNA information, from such a small carrier.

In this case, DNA amplification is needed in the analysis of trace evidence, that is, to amplify the original trace amount of DNA carrier. Only when it is amplified to a certain extent can it continue to be identified and subsequently analyzed.

The instrument used here is called a PCR instrument.

The full name of this thing is PCR gene amplifier, PCR nucleic acid amplifier, and polymerase chain reaction nucleic acid amplifier.

It is an instrument that uses polymerase chain reaction technology to amplify specific DNA.

In the past, this kind of thing was very expensive, often costing millions.

After the monopoly of related polymerase chain reaction technology was broken in the past two years, the price of this instrument has gradually dropped.

But it is not cheap either. The one purchased by Lu Chuan and his team cost 320 million.

The reason why it is so expensive is that DNA amplification instruments have different performance indicators and uses.

Most of the DNA amplification instruments encountered on the market cannot actually be used in the field of criminal investigation.

The ones that can be used in the field of criminal investigation are the most advanced and sophisticated.

At present, it is not possible to produce and manufacture it domestically and can only be purchased from abroad.

Moreover, the reagents used are very expensive.

Basically, it will cost at least 1 yuan to use it once.

So don't underestimate this thing. It's very useful. It's really rude when it comes to burning money. "Just an hour ago, after amplification, the cell material we found on the kitchen knife handle and the third cell material found on the mop handle have the same DNA sequence. I personally think it can prove that this is what the murderer left behind."

Yang Lin finally gave a conclusion.

it is good!
very good!

It can be said that there is always light at the end of the tunnel.

Lu Chuan was still worried just now, and then he arrested Zhang Chao, but the chain of evidence was incomplete, and there was no way to convict the other party without solid evidence.

As a result, within less than two hours, the criminal investigation team gave Lu Chuan peace of mind.

The next task is very simple. First, arrest Zhang Chao, and then take his blood to test the DNA information. As long as the DNA information can be successfully compared with that measured by Yang Lin, the case will be proven to be a solid one.

"Zhao Kai! Arrest him!"

After hanging up the phone, Lu Chuan immediately called Wang Zhaokai.

Arrests?

Wang Zhaokai was confused. Lu Chuan had just told him to keep an eye on the man and not to touch him for the time being, so as not to knock down the police car. He also had to wait for the technical appraisal results from the Criminal Investigation Detachment.

He didn't expect that the order from Lu Chuan would come so soon.

He wanted to ask whether Lu Chuan had relevant evidence, but Wang Zhaokai suppressed the thought.

Since Director Luchuan has given the order, there must be a reason. As an executive, there is no need for me to question the decision of my leader.

Of course, if the leader above was a loser, Wang Zhaokai would definitely ask questions, or even confront him, but Lu Chuan was different.

Working under Lu Chuan gave Wang Zhaokai the most smooth and comfortable feeling.

Although it doesn’t mean that we won’t work overtime or extra hours, that’s not what I mean at all.

To be honest, it is quite tiring to work with Lu Chuan and handle cases because Lu Chuan has a lot of cases on hand.

For example, this case, which was originally a theft case, occurred at the Tianshan District Public Security Bureau.

In terms of the jurisdiction of the case, it should be the Criminal Police Brigade of the Tianshan District Public Security Bureau that should follow up on this case. There is no need for our High-tech Zone to take action.

What's more, the High-tech Zone Criminal Police Brigade had just solved a homicide case here a few days ago, and without even a few days' rest, another homicide case occurred.

In the past, I rarely encountered an allergy throughout the year, and when I did, I would be busy for days, dozens of days, or even months.

But now, murders seem to be commonplace, happening one after another.

People who work on criminal cases are prone to mental stress, and this is even more so when they encounter a homicide case.

So working under Lu Chuan is really tiring. I encounter many cases, travel a lot, and work overtime a lot.

But the sense of accomplishment after solving the case is incomparable.

It was particularly smooth to follow Lu Chuan in handling cases. It seemed that no matter what difficulties they encountered, Lu Chuan could solve them. As long as Wang Zhaokai and the others followed Lu Chuan's ideas, the case seemed to be solved smoothly.

And solving homicide cases is different from solving other cases.

After solving every murder case, there will be rewards. (End of this chapter)