Chapter 231: , The Poet of the Spring-Fighting Department

DNA STR sequencing is very complex to explain; in short, it is a method that typically tests 15-20 core STR loci in a genetic sequence (such as the CODIS system) and confirms whether they are the same person based on whether these points correspond.

If two samples (such as a scene sample and a suspect sample) are completely identical in genotype (allele values) at all loci, they can be identified as the same person.

If one locus is different, it can be considered an experimental error or a genetic mutation at a certain position, meaning the possibility that they are the same person is still retained.

If more than one locus is different, then the possibility of them being the same person can be directly ruled out.

But here is the problem: Igarashi Aiko's own DNA matches her own, so how could 3 loci be different?

At this moment, Ishihara Mikoto spoke up; the Forensic Beauty pointed at the sequencing map: "The sample has been contaminated."

"For example, suppose Igarashi Aiko's sequencing points are A and C, and the contaminator's points are B and D; then the sequencing results will show ABCD simultaneously, and the extra point genes will form a mixed profile."

"Uesugi-kun, Section Chief Watanabe, and everyone from the Metropolitan Police Department, look, this sequencing shows at least three extra alleles, which means that at least three other people's DNA has been mixed into the sample. This has become a mixed sample, so when matched against anyone, the answer for such a mixed sample is always 'no match'."

Ishihara Mikoto said seriously: "This can only prove one thing!"

"The samples were all contaminated; over in Kanagawa, they mixed the evidence collected at the scene together and took it to do the DNA analysis experiment!"

If the contamination level is less than 5%, the computer can barely perform separation; if the contamination level exceeds 30%, the computer cannot distinguish it and re-sampling is required. As for the 5%-30% range, it can be used as a reference for less serious research, but for criminal investigation to be used as evidence in court, only those below 5% can possibly be accepted.

In other words, we're screwed!

"What?!" The people from the Metropolitan Police Department were stunned.

What on earth are those idiots in Kanagawa doing?

Why didn't they tell us about such a big matter?

The one who took the biggest hit was Uesugi Muneyuki; he had originally been one hundred percent certain that the perpetrator's DNA was among the samples identified at the scene.

However, the result of the investigation was that everything was contaminated, every single sample was contaminated; the only thing that wasn't contaminated was the hemorrhoid blood shed by Executive Director Sato!

Damn it! Uesugi Muneyuki slapped the table.

Investigation Division 1 Chief Sugishita Ukyo remained relatively calm, but the others from Investigation Division 1 and the Public Security Police were already cursing.

As expected of Kanagawa, they are all god-tier people!

What should we do now?

Other matters aside, the Special Investigation Headquarters from the Metropolitan Police Department went to the Kanagawa Prefectural Police Headquarters on the spot and found the forensic officer in charge of the DNA testing at the Forensics Division.

This guy refused to admit it at first, saying it had nothing to do with him and that it just came out that way.

As a result, the detectives didn't dare to move him, but Superintendent Ichijo of the Public Security Police pulled out his pistol and pointed it at his forehead: "Then I will arrest you for the crimes of endangering national security, destroying state secrets, and treason. If you have anything to say, you can tell the District Public Prosecutors Office Special Investigation Team after you are sent for prosecution."

Only then was the forensic officer afraid, and he had to explain the reason.

Just as mentioned before, during the on-site forensics, the Kanagawa police did not follow standard procedures to use the evidence numbering label machine, but only used ordinary oil-based markers. Due to the hot weather, the oil-based markers quickly blurred into a mess, so that by the time they were brought back to the Forensics Division, it was impossible to distinguish which was which.

The Forensics Division also just muddled through, rearranged them at random, and took them to do the experiment.

"Why didn't you follow standard procedures? Why didn't you use the evidence numbering label machine?" Uesugi Muneyuki was trembling with rage.

"Because... there was no budget..." the forensic officer said awkwardly: "The approved budget wasn't enough, so we had to save where we could."

"............" The people from the Metropolitan Police Department were speechless.

The detectives from the main department actually knew this; the budgets for local branches were never as sufficient as the Metropolitan Police Department's.

So which part of the funding should be cut?

Wages? Benefits? Or police equipment?

Unfortunately, none of these could be cut, so after cutting here and there, they could only cut less important departments like the Forensics Division.

Thus, under the severe chain contamination of evidence, the first-hand DNA evidence collected by the Kanagawa police was all invalidated.

Uesugi Muneyuki's confident DNA testing was all for nothing.

Helpless, Uesugi Muneyuki turned his attention to another batch of physical evidence, which was the wet trash collected from the sewers and inside the house.

According to his hypothesis, the perpetrator should have stayed in Igarashi Aiko's house for quite a long time; perhaps they would eat something to replenish their strength, and some clues should be found in the trash.

But the Forensics Division of the Kanagawa Prefectural Police Headquarters told Uesugi Muneyuki and the others very embarrassedly.

Due to the hot and humid weather, plus the fact that the Kanagawa police delayed for too long and did not prepare desiccant, by the time the evidence was sent to the Forensics Division, it had molded.

"............" Uesugi Muneyuki discovered that when people are speechless, they really want to laugh.

Is there even a human being in this Kanagawa?

"That's enough, thank you for your cooperation." Uesugi Muneyuki was too lazy to say more and said directly to the Forensics Division of the Kanagawa Prefectural Police Headquarters: "Then see you in the Yomiuri Shimbun."

"What? Hey, wait!" At this moment, the Kanagawa police realized that something big was wrong and hurriedly called the Prefectural Police Chief.

By the time the people from the Metropolitan Police Department were ready to leave, Kanagawa Prefectural Police Chief Takakura had already brought a large group of police to block Uesugi Muneyuki.

"What are you trying to do?" Chief Takakura said sternly: "You actually dare to leak case secrets to the media; are you, are you trying to destroy the Japanese police?"

"You are incompetent and can't find anything, yet you want to leak the news to the media; does the main department even want to solve this case?"

"And what 'Forensic Examiner Uesugi', I think his level is just so-so! Forcing a doctor who doesn't fit in anywhere to join, I see the main department is just like that."

"Not doing proper work, thinking about being a big star all day, not considering the interests of the organization, but you're quite good at infighting!"

The Metropolitan Police Department side also didn't expect the Kanagawa Headquarters to have such an attitude.

They contaminated the evidence themselves, yet they still turned around and blamed others.

Among the several Police Inspectors present, the Non-Career Track Police Inspectors didn't quite dare to make a move, after all, the Career Track naturally suppresses the Non-Career Track by bloodline, but Kashiwagi Jin, who was also Career Track, couldn't care less; he suppressed his anger and was about to roll up his sleeves and give Chief Takakura a punch.

Also bursting with anger were Miss Minami, Okada Keibu, and Ikeda Erena; Erena's fists under her sleeves were clenched tightly, and her ultimate move was already charging up.

Arashi no Yama, Tenchi Gaeshi, Chodai Sotogari! Jigoku Gokuraku Otoshi!

And just at this moment, Investigation Division 1 Chief Sugishita Ukyo stepped out alone, blocking the front of the Metropolitan Police Department and the Kanagawa police, signaling everyone not to be impulsive. He came to Chief Takakura, bowed very politely, and said in standard honorifics: "Chief Takakura, please have a limit to your arrogance. You are merely relying on your seniority being older than ours, your police rank being higher than ours, and this being Kanagawa, wanting to suppress others with power."

"Looking at you like this, fierce in appearance but faint in heart, a tiger's skin on a sheep's body, I think, 'reaching the ninth heaven with a voice like iron, heart hanging by a thread with breath like silk' describes exactly your kind of person? Truly disgusting."

Sugishita Ukyo's words made Chief Takakura's face turn the color of a pig's liver, and he couldn't speak for a long time.

"Let's go!" Investigation Division 1 Chief Sugishita signaled.

"Wait." Uesugi Muneyuki signaled that it wasn't over yet. He walked to Chief Takakura and said very seriously: "Chief Takakura, from afar you look like a crocodile driving a Gundam, how did you turn into a Chihuahua with its tail tucked between its legs when seen up close?"

"Ahhhhhhh!!!!" Chief Takakura was so angry on the spot that he almost fainted.

"Headquarters Chief, Headquarters Chief!!!"

September 24th, the fifth day since the establishment of the Joint Special Investigation Headquarters, and there were still no results.

All key chains of evidence were completely broken.

The salvage operations by Tokyo Marine Holdings and the Japan Coast Guard also yielded no further gains; everything seemed to have turned into an even greater mystery.

While all of Japan was heatedly discussing this case, the *Asahi Shimbun* and the *Yomiuri Shimbun* once again broke sensational news.

"Management Negligence and Lax Training, Key On-Site Evidence Contaminated, Professionalism of Kanagawa Police Questioned."

"A Huge Dilemma, All On-Site Evidence Ruined, Forensic Examiner Uesugi in a Desperate Situation, Can We Still Count on Him This Time?"

As Uesugi Muneyuki exposed the destructive damage the Kanagawa Police had caused to important evidence, the Japanese people were shocked by the Kanagawa Police's operations.

Is this even possible?

Are you people actually police?

Even if a Yakuza passed the exam and put on a police uniform, they would probably be much better than you!

Suddenly, the Kanagawa Prefectural Police Headquarters became the target of public criticism nationwide. On September 25th, the Kanagawa Prefectural Police Headquarters was forced to issue a public apology. The Headquarters Chief, Deputy Chief, Criminal Investigation Department Chief, Security Department Chief, and Police Inspector Yamanaka, who was primarily responsible for investigating this case, bowed to everyone in front of the media.

Hontou ni sumimasen!

That such a thing happened is entirely due to the incompetence of the Forensics Division staff, as well as the lax supervision by us in senior management. It is due to problems such as the vacancy of primary responsibility in the departments involved, the absence of industry management responsibilities by the competent authorities, the failure to implement supervisory and management responsibilities, and improper emergency response work, which have caused a vile social impact; the lesson is extremely profound.

Headquarters Chief Takakura promised that they would earnestly investigate risks, conduct in-depth self-examination and self-correction, strive to grasp the implementation of rectifications, improve emergency handling capabilities, and establish a safe and reliable barrier for evidence.

Of course, now that the Headquarters Chief had bowed and apologized, the involved staff members of the Forensics Division were naturally dismissed.

In an instant, the Kanagawa Police became the laughingstock of all Japan.

People gave them the nickname "Yokohama Sloths" (referring to their slow reactions and slow movements; they do nothing but eat and sleep).

After the press conference ended, the furious Headquarters Chief Takakura found Police Inspector Yamanaka: "There is no choice! We can only do it that way!"

"Headquarters Chief... do we really have to do that?" Police Inspector Yamanaka was clearly somewhat hesitant.

"Heh, don't worry, Yamanaka. Now that all the evidence is destroyed, even a forensic expert like Uesugi Muneyuki is powerless against this case. Since even he can't find anything, there is nothing to worry about... Yamanaka! If this case still cannot be solved, we are all finished!"

"Then... alright."

And so, on that very day of September 25th, before the morning press conference had even finished, by the evening, the Kanagawa Prefectural Police Headquarters held another press conference. At the scene of the press conference, Police Inspector Yamanaka, who was in charge of the case, proudly announced that they had successfully arrested a suspect with a high probability of having committed the crime!

The suspect was named Tanaka Takaaki, 49 years old, unmarried and childless, barely maintaining his life by doing odd jobs everywhere. However, at noon that day, he had taken a pair of gold rings to a jewelry store to sell them.

This immediately aroused the suspicion of the jewelry store staff. How could a somewhat slovenly middle-aged man who couldn't explain his background have obtained this pair of gold rings?

So they asked the store manager to come and look. The store manager found that there was nothing wrong with the gold rings, but he could not accept gold of such unknown origin.

At this moment, the store manager also recalled the Tokyo Bay body-dumping case and the Yokohama Mitsui female executive murder case that all of Japan had been paying attention to recently. He suddenly remembered that in the photo on the missing person notice, Igarashi Aiko seemed to be wearing these very gold rings.

After comparing them, it really was them!

While stalling Tanaka Takaaki, the store manager called the police, and they finally succeeded in capturing this major suspect.

In the end, after confirmation by the family, the gold rings were indeed the pair belonging to Igarashi Aiko.

Everything seemed to have cleared up.

The Joint Special Investigation Headquarters and the Metropolitan Police Department also received the news and watched the press conference together.

"Damn it, did Kanagawa beat us to it?" Police Inspector Kashiwagi and the others were very frustrated.

Only Uesugi Muneyuki, who was watching the scene of the press conference, showed a look of confusion.

Gold rings?

That's not right, is it?

I remember in the Death Flashback, after Igarashi Aiko returned home, she first took off her rings at the door and put them in a small box in the entryway cabinet, and then she was attacked after reaching the second floor.

After the attack, the murderer should have been in a hurry to take Aiko away, and there were no signs of searching in the house; how could they have gone out of their way to return to the first floor to take the gold rings?

Even if they took the gold rings, given the level of care and seriousness the two murderers prepared for the crime, how could they take them out to sell at this time?

Why was it that they had just finished apologizing at a press conference in the morning, and by the evening, they had caught a major suspect?

A flash of inspiration suddenly exploded in Uesugi Muneyuki's mind.

Could it be...

You really are yourselves, Kanagawa Police.

"You are all idiots!" (A pun on "You are all idiots!")

Wait!

Although this is a "fishing" operation by the Kanagawa Police, but... if it could be applied to Igarashi Aiko's case...

"I think we may have overestimated the lower limit of the Kanagawa Police, and far overestimated their upper limit." Uesugi Muneyuki suddenly said to everyone in the conference room: "We have been making a huge mistake all along!"

"We have always been guessing the murderer based on the Kanagawa Police's reports, Igarashi Aiko's status as an executive, her relationships with people around her, and the possible retaliation against her father, Igarashi Masataka."

"But is there a possibility that there are other circumstances we have ignored?"

"That is, some clues were not considered by the Kanagawa Police from the beginning, or rather, some parts that we have never come into contact with are the key to solving the case?!"

"Uesugi-kun, what do you mean?" Sugishita Ukyo was thoughtful: "We walked into a trap?"

"Yes!" Uesugi Muneyuki slammed his fist down: "We started this case halfway through, not investigating it completely from the beginning!"

"This time, don't consider the workplace, don't consider the enterprise, and don't consider her father's connections!"

"Just conduct the investigation based on her as an individual!"

"There must be something we have ignored, there must be something we have subconsciously excluded!"

"Discard all impossible options, and perhaps the remaining one, which seems the most bizarre and which we wouldn't even think of, might just be the truth!"

(End of chapter)