Marles is an ordinary Nordic town.

It has a gentle and clean river, but it is frozen for six months a year, and the rest of the time it is often floating with broken ice. It has a beautiful fitness trail, wide and straight, with beautiful shock-absorbing boards, but three people died on it.

Marles is most famous for lithographs, which can be traced back to the Viking era, but no one wants to see these lithographs. They may be works of art or antiques, but it was not until someone's blood soaked the land that a camera came to this cold city.

Yang Rui jumped out of the car, and the snow was creaking under his feet.

Yang Rui looked into the distance and could see the distant snow-capped mountains and the houses at the foot of the mountain.

"What a wide place." Yang Rui exclaimed: "There can be a distance of 100 meters between a house."

"Swedes like to live farther away. We don't like to hear the sounds of neighbors' homes, whether they are talking or shooting." Officer Ackerman closed the car door heavily and followed Yang Rui.

Yang Rui's PCR technology identified Ackerman's hair, which made him instantly become a fan of PCR technology. Not only that, he also found information to read by himself - Swedes are either social people, but their favorite things are squatting in the corner of the world and studying their own gadgets.

“There are 874 permanent residents in Marlá,” Ackerman asked: “Where do you want to start?”

"We must first identify the residents of the town. If it is not done by people from other towns, we can just collect the residents' DNA. To be on the safe side, please do it under our guidance." Yang Rui's explanation has actually been communicated before, and it is just a repeated explanation.

Ackerman just needs such a repeated explanation.

PCR is a new thing for everyone, and everyone has to confirm it repeatedly to avoid making mistakes in the steps and affecting the results - in fact, Yang Rui emphasized this point.

The residents of the town were notified in advance and gathered quickly.

This may be unimaginable in the United States. You cannot expect the Americans in a town to gather on time in a regular manner, but the Swedes can, whether it is a month in advance or a day in advance, as long as the time is determined and confirmed, they will get everyone.

The descendants of these Viking Pirates were taciturn, but they appeared on time at the gathering place as if they were preparing to board the boat.

"Didn't you think?" Huang Mao walked behind Yang Rui and said, "Look at these Swedes, they all look ordinary. Who can guess that there can be a murderer inside."

"It can't be said to be ordinary. Many people are over 1.9 meters tall." Yang Rui shrugged.

"It's similar to you." Huang Mao looked up at Yang Rui enviously and said, "Why do you think you look as tall as Nordics? No, it's taller than many Nordics."

"God-given." Yang Rui said sincerely.

Huang Mao laughed.

"In a while, we will use cotton swabs to stir it in your mouth and will not damage your body. This is the latest technology to do necessary tests..." A senior police officer held the microphone and introduced the situation to the residents. His voice was dull, as if he was talking about an ordinary little thing.

The residents also seemed to be listening to something ordinary.

Instead, Yang Rui stood below, picked up his red flag camera, and when the first resident started sampling, he pressed the shutter desperately.

In the era when a volume of photos was less than 30, his shutter quickly could not be pressed.

Yang Rui laughed twice, opened the back cover of the camera, carefully put the film away, and then said to Jing Yulan next to him: "From now, these will be regular historical materials."

"Historical material?" Jing Yulan was carrying an LV bag, wearing a lady's hat with wide brim, and sunglasses were hanging on the bridge of her nose to prevent snow blindness. From a distance, she looked like a beautiful girl at the forefront of fashion.

Yang Rui put her hand on her waist, hugged her gently and let go, and smiled and said, "The first time in human history in which PCR is used to handle a case is of course historical material. This must be in the museum in the future."

"You think it's very important, what if others don't?" Jing Yulan joked with a smile.

Yang Rui thought for a while and said, "Then I will build a museum myself." Yang Rui's answer was very clear, which made Jing Yulan a little stunned.

KAKA.

Yang Rui instantly pressed out another photo.

During the entire sampling process, Huang Mao, Tu Xian and others supervised and assisted the whole process.

Sampling is the most important step. For PCR itself, there are fewer mistakes, but once sampling errors occur, all of them will be done.

Yang Rui looked very relaxed, but in fact he was so nervous.

If the murderer is not among the residents, if the sampling error occurs, if the technician has problems with the operation... what he wants is a big news, not a big scandal.

However, this is how you do things. You have to accept acceptable risks. If you cannot accept them, you will end up early. If you can accept them, you will not regret it.

The trip to Marlas ended soon.

Yang Rui returned to Stockholm and just started sorting out the samples, Director Sherwood called him into the office and asked: "Mr. Yang Rui, how long will it take to receive the results? I mean, how long will it take to confirm the murderer."

"If you are lucky, tomorrow, if you are not lucky, it will probably take two or three days." Yang Rui said: "Our PCR instrument is not enough to make all samples at once."

"That is, it takes three days to make a complete sample? Only 300 can be made a day?" Director Sherwood calculated and asked, "Can you find more?"

"In fact, we can only do not have 200 samples a day, and we don't need to make complete samples. We can rule out some."

"Huh? It can be ruled out, but will not miss people because of this? Mr. Yang Rui, you should know that it takes some work to pass PCR technology from a judge. If it makes a mistake the first time, it will be difficult to pass it again."

Yang Rui smiled and said, "It will not be missed. We only excluded it when we are sure. In fact, we only excluded women."

"Isn't it a woman who commits the crime?"

"Well, because the murderer's DNA is male." Yang Rui briefly told Sherwood about the relationship between X and Y chromosomes, and said: "If the genome project is completed, we can rule out more things. At present, the safest way is to exclude women and then start testing from young and middle-aged residents. At the same time, the female sample was taken to avoid unexpected situations."

If the human genome project is completed, or go further, and you can learn more about the human genes, you can get the murderer's DNA and draw a very detailed facial mask, such as race, skin color, age, etc., which are easy to obtain. Whether it is a hook nose or rosacea, curly or straight hair, there are traces to follow.

However, the 1986-year-old human genome project is still in its infancy, and there is almost no useful thing, at least there is nothing that can be used immediately at this time. Yang Rui just said that.

Sherwood was not going to ask for more scientific details. The information Yang Rui told him had already made Sherwood quite satisfied and smiled: "This is the best. I have talked to the judge. They will understand this technology independently, but I believe there is no problem..."

Although the concept of DNA had appeared as early as the 1950s, DNA as evidence is new around the world, and the judicial system of every country needs an acceptance process.

Yang Rui had an idea earlier, and when she heard Sherwood say this, he couldn't help but say, "I have a suggestion."

"kindness."

"You may be able to use some relatively certain small cases as examples of PCR application. If you pass it once, can you solve the problem of judicial determination?" Yang Rui used rare English words and talked with Sherwood in a difficult manner.

He does not need the Marla case to be the first case of PCR instruments. Such a first case has limited support for news, and what he needs is a solid case.

If the value of the PCR instrument can be perfectly proved and then promoted that PCR solves complex cases, it may be more meaningful for Yang Rui.

Sherwood was a little surprised and said, "Do you want to use a PCR device to solve a few cases first?"

"Yes. If you don't make it easy to arrange funds, we can provide trial services."

"No. If it's just a small case, the cost is not a problem." Sherwood obviously didn't care about the expenses of tens of thousands of kroners, but just murmured: "You are very confident about the PCR device."

"Of course." Yang Rui laughed. DNA identification is known as the king of physical evidence. For a considerable period of time, the judicial systems of various countries worshipped DNA like gods.
Chapter completed!