Tokyo Unnatural Forensics

Chapter 227, Izumi Tobu Poet
DNA STR sequencing is very complex. In short, it is a method that typically detects 15-20 core STR sites in a gene sequence (such as the CODIS system) and confirms whether the individuals belong to the same person based on whether these sites match.

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

If there is a difference at one locus, it can be considered as experimental error or gene mutation at a certain location, thus preserving the possibility that it may be the same person.

If there are more than one different location, then the same person can be ruled out directly.

But here's the problem: how could there be three different DNA markers when Aiko Igarashi's DNA matches her own?

At this moment, Mikoto Ishihara spoke up, the forensic expert pointing to the sequencing data: "The sample is contaminated."

"For example, suppose Aiko Igarashi has sequencing sites A and C, and the contaminated person has sites B and D. Then the sequencing results will show ABCD at the same time, and the extra site genes will form a mixed pattern."

“Uesugi-kun, Section Chief Watanabe, and everyone in the Metropolitan Police Department, look, this sequencing has revealed at least three additional alleles. This means that the sample contains DNA from at least three other people, making it a mixed sample. Therefore, the answer to this mixed sample is 'no match' when it comes to matching anyone.”

Mikoto Ishihara said earnestly, "This can only prove one thing!"

"The samples were all contaminated. In Kanagawa, they mixed the evidence collected at the scene together and took it for DNA analysis!"

If the contamination level is less than 5%, the computer can still barely separate the contamination. If the contamination level exceeds 30%, the computer cannot distinguish it and resampling is required. As for the 5%-30% range, this range can be used as a reference for less serious studies, but for criminal investigations, only those below 5% can be accepted as evidence in court.

In other words, it's spicy!
"What?!" Everyone in the Metropolitan Police Department was stunned.

What are those idiots in Kanagawa doing?
Why didn't you tell us about something so important?

The one who was most affected was Uesugi Muneyuki, who was 100% certain that the killer's DNA was among the samples identified at the scene.

However, the results showed that everything was contaminated, every single sample was contaminated, the only one that was not contaminated was the hemorrhoid blood that came out of Executive Director Sato!

"Damn it!" Uesugi Muneyuki slammed his hand on the table.

Section Chief Sugishita Ukyo remained relatively calm, while the other members of the First Investigation Division and the Public Security Police had already started hurling insults at each other.

As expected of Kanagawa, everyone here is a genius!
What to do now?
Putting other matters aside, the Special Investigation Headquarters of the Metropolitan Police Department immediately went to the Kanagawa Police Headquarters and found the forensic officer in charge of DNA testing.

At first, this guy denied it, saying it had nothing to do with him and that's how the test came out.

As a result, the criminal police dared not touch him, but a police inspector directly pulled out a pistol and pressed it against his forehead: "Then I will arrest you for endangering national security, destroying state secrets, and treason. You can talk to the district prosecutor's special investigation team after the case is sent to the prosecutor's office."

The forensic officer was then frightened and had no choice but to reveal the reason.

As mentioned earlier, during the on-site identification, the Kanagawa police did not use the standard procedure of using an evidence numbering and labeling machine, but instead used an ordinary oil-based marker. Due to the hot weather, the oil-based marker quickly became a mess, making it impossible to distinguish which items were which when they were brought back to the forensic department.

The forensic department also did a shoddy job, simply rearranging the items and using them for experiments.

"Why not follow the standard procedures? Why not use the evidence numbering and labeling machine?" Uesugi Muneyuki was trembling with anger.

"Because... there's no budget..." the forensic officer said awkwardly, "The approved budget isn't enough, so we have to cut costs wherever possible."

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

The detectives at this department are actually aware of this, as the budgets of local branches have never been as ample as those of the Metropolitan Police Department.

So which part of the budget should be cut?
Salary? Benefits? Or police equipment?

Unfortunately, none of these departments could be cut. In the end, after much back and forth, the only thing left to cut were less important departments like the forensic science department.

As a result of severe chain reaction of evidence contamination, all the first-hand DNA evidence collected by the Kanagawa police became invalid.

Uesugi Muneyuki confidently underwent DNA testing, and all results came back negative.

Left with no other option, Uesugi Muneyuki turned his attention to another batch of physical evidence: samples collected from the sewers and wet waste inside the house.

Based on his speculation, the murderer must have stayed at Aiko Igarashi's house for quite a while. Perhaps they ate something to replenish their energy, and they should have been able to find some clues in the trash.

However, the forensic department of the Kanagawa Police Headquarters told Uesugi Muneyuki and the others with some embarrassment.

Due to the hot and humid weather, coupled with the fact that the Kanagawa police had been delayed for too long and had not prepared any desiccants, the evidence had become moldy by the time it was delivered to the forensic department.

"…………" Uesugi Muneyuki found himself wanting to laugh when people were speechless.

Are there still humans in Kanagawa?

"That's enough, thank you for your cooperation." Uesugi Muneyuki didn't bother with further words and directly addressed the forensic department of the Kanagawa Police Headquarters: "See you at the Yomiuri Shimbun."

"What? Wait a minute!" At this moment, the Kanagawa police realized that something was seriously wrong and quickly hung up the phone to call the police chief.

Just as the officers from the Metropolitan Police Department were about to leave, Kanagawa Prefecture Chief Takakura, along with a large group of police officers, blocked Uesugi Muneyuki's path.

"What are you trying to do?" Chief Takakura's voice was stern. "How dare you leak case secrets to the media! Are you trying to destroy the Japanese police?"

"You're incompetent and can't find anything, yet you want to leak information to the media. Does this department even want to solve this case?"

"And this so-called Uesugi forensic examiner? I think his level is just so-so! By having to bring in this kind of doctor who doesn't know anything about anything, I think the Central Bureau is just like that."

"He doesn't do his job properly, all he thinks about is becoming a big star. He doesn't consider the interests of the organization, but he's very good at infighting!"

The Metropolitan Police Department was also surprised by the Kanagawa headquarters' attitude.

They contaminated the evidence themselves, yet they still tried to shift the blame.

Among the inspectors present, the non-professional inspectors were hesitant to make a move, as the professional team naturally had a bloodline advantage over the non-professional team. However, Kashiwagi Jin, who was also a professional inspector, didn't care about such things. He suppressed his anger and was about to roll up his sleeves and punch Chief Takakura.

Also bursting with anger were Minami, Inspector Okada, and Erena Ikeda. Erena's fists were clenched tightly under her sleeves, and she was already gathering her power for a powerful attack.

Mount Arashi, heaven and earth reversed, a massive external slash! Hell and paradise fall!

At that moment, Sugishita Ukyo, the head of the First Investigation Division, stepped forward and stood in front of the Metropolitan Police Department and Kanagawa police, signaling everyone not to act rashly. He approached Chief Inspector Takakura, bowed politely, and said in standard honorifics, "Chief Inspector Takakura, there is a limit to your arrogance. You are just trying to intimidate us because you are more senior than us, have a higher rank, and are in Kanagawa."

"Looking at you, all bark and no bite, a sheep in tiger's skin. I think the saying 'Those who hold the highest position in the court have voices like iron but hearts hang by a thread and breaths like silk' perfectly describes you. You are truly disgusting."

Sugishita Ukyo's words caused Chief Takakura's face to turn a deep shade of liver, leaving him speechless for a long time.

"Let's go!" Section Chief Sugishita gestured. "Wait." Before Uesugi Muneyuki could finish gesturing, he walked up to Chief Takakura and said seriously, "Chief Takakura, from a distance you look like an alligator piloting a Gundam, but up close you look like a Chihuahua with its tail between its legs?"

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

"Chief, Chief!!!"

On September 24, the fifth day since the establishment of the Joint Special Investigation Headquarters, the investigation had still yielded no results.

All the key chains of evidence have been broken.

The salvage operation by Tokyo Marine Holdings and the Japan Coast Guard yielded no further results, and everything seemed to have become an even bigger mystery.

While the entire nation was discussing this case, the Asahi Shimbun and Yomiuri Shimbun broke another bombshell.

"Poor management and inadequate training led to the contamination of crucial on-site evidence, casting doubt on the professionalism of the Kanagawa Police."

A colossal problem: all evidence at the scene is rendered useless, and forensic investigator Uesugi is on the verge of death. Can we still count on him this time?

The Japanese public was shocked by the Kanagawa police's actions after Uesugi Muneyuki exposed their devastating destruction of important evidence.

Is this even possible?

Are you even police officers?

Even if someone from the Yakuza got in and wore a police uniform, they'd probably be way better than you guys!

In an instant, the Kanagawa Police Headquarters became the target of nationwide criticism. On September 25, the Kanagawa Police Headquarters was forced to issue a public apology. The head of the headquarters, the deputy head of the headquarters, the head of the criminal investigation department, the head of the security department, and Inspector Yamanaka, who was in charge of the investigation, bowed to everyone in front of the media.

Red bean paste private Marseille!
This incident occurred entirely due to the incompetence of the forensic staff, the lack of oversight from higher-ups, the failure of the responsible departments to fulfill their industry management duties, the ineffective implementation of supervisory and management responsibilities, and the mishandling of emergency response measures. These issues have caused a severe negative social impact and serve as a profound lesson.

General Manager Takakura promised to thoroughly investigate risks, conduct in-depth self-examination and rectification, focus on implementing corrective measures, improve emergency response capabilities, and establish a reliable barrier for the safety of evidence.

Of course, the chief apologized, and the forensic officer involved was dismissed.

For a time, the Kanagawa police became a laughing stock throughout Japan.

It is nicknamed "Yokohama Sloth" (meaning it is slow to react and move, and does nothing but eat and sleep).

After the press conference, a furious Chief Inspector Takakura confronted Inspector Yamanaka: "There was no other choice! We had to do it that way!"

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

"Heh, don't worry, Yamanaka. All the evidence is destroyed now. Even a forensic expert like Uesugi Muneyuki is powerless to solve this case. Since even he can't find out, there's nothing to worry about... Yamanaka! If this case can't be solved, we're all doomed!"

"OK then."

So on September 25th, before the morning press conference had even ended, the Kanagawa Police Headquarters held another press conference that evening. At the press conference, Inspector Yamanaka, who was in charge of the case, proudly announced that they had successfully arrested a suspect with a high probability of committing the crime!
The suspect, named Takaaki Tanaka, 49, was unmarried and childless and barely made a living by doing odd jobs. However, on this particular day at noon, he took a pair of gold rings to a jewelry store to sell.

This immediately aroused the suspicion of the jewelry store employees. How did a slightly slovenly middle-aged man with an unclear background obtain these gold rings?

So they asked the store manager to take a look. The store manager found that there was nothing wrong with the gold ring, but he could not accept gold of unknown origin.

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

After comparing them, it really is true!
While keeping Tanaka Takaaki calm, the store manager called the police, and they eventually succeeded in arresting the prime suspect.

Ultimately, after confirmation by the family, the gold ring was confirmed to be the wedding ring belonging to Aiko Igarashi.

Everything seemed to be taking a turn for the better.

The Joint Special Investigation Headquarters and the Metropolitan Police Department also received the news, so let's watch the press conference together.

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

Only Uesugi Muneyuki, who was watching the press conference, looked puzzled.

Gold ring?
Right?
I remember in the death flashback, after Aiko Igarashi returned home, she first took off her ring at the door and put it in a small box in the cabinet by the door, and then went upstairs where she was attacked.

After the attack, the perpetrator should have been in a hurry to take Aiko away. There were no signs of ransacking in the house, so why would they go back downstairs to retrieve the gold ring?
Even if they took the gold ring, given how meticulous and serious the two murderers were in preparing for the crime, why would they take it out to sell at this time?

Why was a major suspect arrested in the evening after a press conference to apologize in the morning?
A sudden flash of inspiration struck Uesugi Muneyuki.

Could it be...

As expected of you, Kanagawa police.

Poet of the Izumi-dou clan!
and many more!

Although this was a sting operation by the Kanagawa police, ... if it could be applied to the case of Aiko Igarashi...

"I think we may have overestimated the limits of the Kanagawa police, and far overestimated their potential," Uesugi Muneyuki suddenly said to everyone in the conference room. "We've been making a huge mistake all along!"

"We have been guessing the culprit based on the Kanagawa police reports, Aiko Igarashi's position as a department head, her relationships with those around her, and the possibility of revenge against her father, Masataka Igarashi."

"But is it possible that we've overlooked other situations?"

"So, some clues that the Kanagawa police didn't consider from the beginning, or rather, some parts that we never came into contact with, are the key to solving the case?!"

"Uesugi-kun, what do you mean?" Sugishita Ukyo asked thoughtfully, "We've fallen into a trap?"

“That’s right!” Uesugi Muneyuki slammed his fist down: “We started this case halfway through, instead of investigating it from the very beginning!”

"This time, don't think about the workplace, don't think about the company, and don't think about her father's relationship!"

"Let's start the investigation based on her personally!"

"There must be something we've overlooked, something we've subconsciously excluded!"

"Discard all impossible options, and perhaps the most bizarre answer that remains, one that we would never even consider, is the truth!"

(End of this chapter)