Japan - Miyazawa family of 4 murdered, Setagaya, Tokyo, 30 Dec 2000 #2

[Incoherent]

For some context, my POI was experiencing life changes that, seemingly, left him feeling rage. He could well be innocent of any crime, of course. But it 'feels' right that someone might be unable to lash out at the architect of their pain and therefore seek out other, more vulnerable surrogates...

To me this reads like a military brat. Forced to move around and having decisions made for them. Just based on what I understand you seem to agree with about the killer’s profile - being military, Asian-American, 15-early 20’s, able to leave Japan relatively quickly with not much of a trace. Relatively athletic, as most would be at that age. Diet consistent with living in Japan or Asian parents. Presence in the community but unremarkable, blended into society, went to school or work part time. No direct link to the Miyazawa’s but able to see and watch them by way of presence in the park, surroundings, station. Desire to kill.
Could also be way off I also think there’s other points I’ve missed or haven’t thought about yet.

Close? Or totally wrong? Either way I’d love to know.

 

[FacelessPodcast]

The passage of time makes it difficult for me to judge certain things. The balcony, for example. Looking at the newer pictures, the balcony looks quite weak and like it could fall down soon. I look at it and think I wouldn't want to attempt climbing it. The railing looks like it would barely hold any weight.

But presumably that's the result of age and decay, and it didn't look like that 23/24 years ago. I haven't seen a really clear picture of the balcony from the time of the murders to make a truly informed decision.

Until they catch the killer, I don't think any decision can be truly informed. As you say, that it may be in bad condition 23 years later is neither here nor there. The whole house is in bad condition, part of the reason the TMPD want to knock it down is precisely for this. Add into that constant seismic activity and it's a matter of time. But let's consider a picture taken at the time. There's nothing here that dissuades me, personally, that this wasn't the point of entry. On the balance of probability, Rei's balcony by far and away makes the most sense to me. Clearly it's reasonable to assume it could hold the weight of a slender 5 ft 6 young man.

Bathroom window: noisy, difficult, and zero fibres or prints there.
Front door: almost impossible given the order of the murders / lack of apparent relationship / zero blood found there.
Rei's balcony: never discussed by the TMPD. But I'd bet my life they have considered it and know more than they've said.

 

[Incoherent]

The passage of time makes it difficult for me to judge certain things. The balcony, for example. Looking at the newer pictures, the balcony looks quite weak and like it could fall down soon. I look at it and think I wouldn't want to attempt climbing it. The railing looks like it would barely hold any weight.

But presumably that's the result of age and decay, and it didn't look like that 23/24 years ago. I haven't seen a really clear picture of the balcony from the time of the murders to make a truly informed decision.

The house in person looks dilapidated. It doesn’t look in a great state. It is wooden in structure. Couple that with the amount of earthquakes we get here in Tokyo on the regular, typhoons too, and many since 2000 that would decimate places that aren’t Japan, it’s safe to say the house has been shaken up and not as good as it would have once looked. I also understand the house has been slated for demolition since 2019.
In 2000 however I don’t doubt it would’ve looked fresh and sturdy. After all the Miyazawa’s moved in during the early 90’s and likely had the house built after purchasing the land - it would’ve looked great, albeit small and cramped on the Miyazawa side. But after zero care over 24 years it is a shell of its former self.

 

[FacelessPodcast]

To me this reads like a military brat. Forced to move around and having decisions made for them. Just based on what I understand you seem to agree with about the killer’s profile - being military, Asian-American, 15-early 20’s, able to leave Japan relatively quickly with not much of a trace. Relatively athletic, as most would be at that age. Diet consistent with living in Japan or Asian parents. Presence in the community but unremarkable, blended into society, went to school or work part time. No direct link to the Miyazawa’s but able to see and watch them by way of presence in the park, surroundings, station. Desire to kill.
Could also be way off I also think there’s other points I’ve missed or haven’t thought about yet.

Close? Or totally wrong? Either way I’d love to know.

Pretty much on the money!

 

[Incoherent]

Until they catch the killer, I don't think any decision can be truly informed. As you say, that it may be in bad condition 23 years later is neither here nor there. The whole house is in bad condition, part of the reason the TMPD want to knock it down is precisely for this. Add into that constant seismic activity and it's a matter of time. But let's consider a picture taken at the time. There's nothing here that dissuades me, personally, that this wasn't the point of entry. On the balance of probability, Rei's balcony by far and away makes the most sense to me. Clearly it's reasonable to assume it could hold the weight of a slender 5 ft 6 young man.

Bathroom window: noisy, difficult, and zero fibres or prints there.
Front door: almost impossible given the order of the murders / lack of apparent relationship / zero blood found there.
Rei's balcony: never discussed by the TMPD. But I'd bet my life they have considered it and know more than they've said.

View attachment 488627

You’re always on my exact wavelength with this.

 

[Frankie Hellis]

Yes exactly. Honestly, all of the potential entry points have their problems in one way or another. But Rei's balcony is by far the most logical / least problematic of them all. Did you see the video from @Incoherent ? It shows the rear bathroom window is physically possible but seems totally implausible. The sequence of the murders themselves and lack of known relationship with the family stands against him using the front door. To me, that leaves this balcony.

And for sure, I think he *chose* them. He had a specific reason. How directly or indirectly they were involved in his reasoning? That's the 64-million-dollar question.

I saw that in the video! I didn’t think it was so doable. It looks more difficult than the guy made it look in the video. The only thing is I do not see how he could have entered through the bathroom window and the crime have unfolded the way the crime scene indicates. Everyone would have heard him coming through that window, I think.

 

[Incoherent]

I saw that in the video! I didn’t think it was so doable. It looks more difficult than the guy made it look in the video. The only thing is I do not see how he could have entered through the bathroom window and the crime have unfolded the way the crime scene indicates. Everyone would have heard him coming through that window, I think.

Definitely no small feat getting into that bathroom. All I can think of that helped mask the noise if it was the bathroom window is:
1. The air con units all running would create a buzz or humming noise surrounding the house, and Mikio was sat very close to 2 of them on Rei’s balcony and another in front of him located on the side of the house.
2. The killer did make noise getting in, but not enough to trigger a warning, so Mikio thought it might be Yasuko or Niina coming down from the ladder for the bathroom, or Rei.

But we also likely know that by the time Rei was dead Mikio had realised something was wrong and rushed up the stairs.

A very awful question to think about, but just how long does it take a strangled child to die? Quick enough that it could be done after entering the bathroom window and before Mikio twigged about the noise?

 

[Charlot123]

Yes, it was USG which is the podcast arm of Universal Studio Group. I completely understand her stance on not wanting to engage with the press. My only point was, I was "offering something in return", as it were. I've said many times, there is no single road map to dealing with grief or victimhood. But I think if it were me and I pleaded with the press to do everything they could to identify the killer, if a member of said press came to me offering the chance at doing this very thing, I would at least discuss the possibility with them.

MOO - everyone in her family probably has serious PTSD. They all must have been excluded from the suspect list, and DNA should rule it out in their case, but the connections between definite family members can be complicated, even ambiguous.

Two sisters, there is SILs, BILs, MILs, FILs, plus, three kids, Niina's friends, her cousin's friends. The bigger the family system, the more complex the relationships between its members. And yet, most have never read anything about the inner lives of either family. Is it good or bad for the case? Either neutral, or, it could have solved the case a long time ago. However, lack of information protects both Ann Irie's family and the deceased Miyazawas from gossips or idle questions. Do you remember how much dirt the media manages to dig about anyone marginally featured in criminal cases? I think Ann's intense reaction to Asahi reporters (who assumed that the murderer was "the family acquaintance bearing a strong feeling of resentment") served to protect both own and Yasuko's and families, given that the houses are separated by a tiny wall. And, if there were any wrinkles on the fabric of the Miyazawas family life, Ann is protecting the deceased from public judgment.

She is the older sister. Maybe in her mind, the killer is dead. Or perhaps she believes that her silence serves to protect the good name of her family.

Ann Irie appears very emotional, though. I wonder, if she thought that the killer was a random dude from another country, maybe even an animal-killer, or a stalker, who broke into an unknown house and executed four family members - would she have not turned all her ballistic anger against that person?

Why hasn't she? She looks like a warrior. She lived outside of Japan long enough. I simply think that she has a very different scenario in her mind.

 

[Charlot123]

I saw that in the video! I didn’t think it was so doable. It looks more difficult than the guy made it look in the video. The only thing is I do not see how he could have entered through the bathroom window and the crime have unfolded the way the crime scene indicates. Everyone would have heard him coming through that window, I think.

Again, we are 23+ years in time from that day. If it were today, I'd think, the guy was into parkour, especially since Tokyo has one of the best parkour parks. However, the sport started in France in the end of the 90es. I doubt that it even reached the US at that time, much less Japan. Now, I remember how in one of these boards they discussed that the young man could be from France. The reasoning seemed odd to me (something about not flushing because of plumbing?? I noticed that while i think the perp did not flush out of spite, the Japanese on the boards provide a more practical explanation to his behaviors.) However, if, in fact, the young man was engaged in parkour and used this skill, in 2000, he probably could have come only from France.

Another person who could scale up the house easy would be a lineman of electric lines. They can climb up the balcony, and they are unnoticeable. Hence, I want to ask whether there is a line of lanterns behind the Miyazawas house, or something like it? This would serve as a good reason to even be behind their house that night.

One more consideration. If the blog about the killing was made by the perpetrator, he is thinking in Japanese categories. The thing is, most of the people I know would view year 2000 as the beginning of the next century and millennium. The young man says he wants to celebrate the new century, e.g., 2001. I am not sure if a person living on the base would think so. JMO.

世田谷一家殺人事件 黒ムツによる事件前と事件後の気になる書き込み | これ知っておけばOK!（簡単にすぐ分かる!）

blog.broadcreation.com

The Kuromitsu 2chan post. I can't imagine any European or American who would not think the XXI century started in 2000. So, this person, if he was involved, thinks like a Japanese man.

According to this article, there is a dissent among scientists and some institutions about the beginning of a new millennium, but country-wise, it was only Japan that counted it since 2001.

World: Which Is The True Third Millennium Year, 2000 Or 2001?

Which is the real millennium year, the outgoing 2000 or the incoming 2001? Despite the worldwide celebrations last January 1, the controversy over the beginning of the true Third Millennium is far from over. RFE/RL correspondent Eugen Tomiuc presents the arguments on both sides. Prague, 28...

www.rferl.org

 

[FacelessPodcast]

Definitely no small feat getting into that bathroom. All I can think of that helped mask the noise if it was the bathroom window is:
1. The air con units all running would create a buzz or humming noise surrounding the house, and Mikio was sat very close to 2 of them on Rei’s balcony and another in front of him located on the side of the house.
2. The killer did make noise getting in, but not enough to trigger a warning, so Mikio thought it might be Yasuko or Niina coming down from the ladder for the bathroom, or Rei.

But we also likely know that by the time Rei was dead Mikio had realised something was wrong and rushed up the stairs.

A very awful question to think about, but just how long does it take a strangled child to die? Quick enough that it could be done after entering the bathroom window and before Mikio twigged about the noise?

10-11lbs of pressure to stop blood flow, brain damage can occur in 30 seconds, death somewhere after 4 minutes. This is all ball park. So, it's not quick like in the movies. However, Rei is found face-down. It's possible the killer smothered him with a pillow or being face-down hastened it.

 

[FacelessPodcast]

MOO - everyone in her family probably has serious PTSD. They all must have been excluded from the suspect list, and DNA should rule it out in their case, but the connections between definite family members can be complicated, even ambiguous.

Two sisters, there is SILs, BILs, MILs, FILs, plus, three kids, Niina's friends, her cousin's friends. The bigger the family system, the more complex the relationships between its members. And yet, most have never read anything about the inner lives of either family. Is it good or bad for the case? Either neutral, or, it could have solved the case a long time ago. However, lack of information protects both Ann Irie's family and the deceased Miyazawas from gossips or idle questions. Do you remember how much dirt the media manages to dig about anyone marginally featured in criminal cases? I think Ann's intense reaction to Asahi reporters (who assumed that the murderer was "the family acquaintance bearing a strong feeling of resentment") served to protect both own and Yasuko's and families, given that the houses are separated by a tiny wall. And, if there were any wrinkles on the fabric of the Miyazawas family life, Ann is protecting the deceased from public judgment.

She is the older sister. Maybe in her mind, the killer is dead. Or perhaps she believes that her silence serves to protect the good name of her family.

Ann Irie appears very emotional, though. I wonder, if she thought that the killer was a random dude from another country, maybe even an animal-killer, or a stalker, who broke into an unknown house and executed four family members - would she have not turned all her ballistic anger against that person?

Why hasn't she? She looks like a warrior. She lived outside of Japan long enough. I simply think that she has a very different scenario in her mind.

They were all ruled immediately through finger-printing. An Irie has spoken many times about her relationship with the family in both interviews and her own books. The one part I recall: where she says she wishes they had been closer and she wishes she hadn't let Mikio install the soundproofing, which would have allowed her to hear what was happening on the night (caveat to say this is not what my sound expert said, the existing soundproofing would not have stopped any noise passing through). I can only say what I saw between the two sides and that's there was a rift. I won't go into detail but it was there. My problem with the idea that An is protecting the family is that she is also often in the public eye at the same time. Her books, interviews, work as a lecturer, seminars (which she charged us money to watch before declining to speak with us), it's all out there. She is not silent.

I can understand that she took exception to the FBI profiler saying he thought the killer was either in the family or close to it. But she does not know if the killer is dead. Whatever scenario she has in her mind, she does not know. But there is a possibility the killer's DNA was in that house. And I was offering a way of knowing more. Even if she had declined the interview, we still would have given her those resources. As I've said many times, I make no judgements on her. I just find it puzzling.

 

[FacelessPodcast]

Again, we are 23+ years in time from that day. If it were today, I'd think, the guy was into parkour, especially since Tokyo has one of the best parkour parks. However, the sport started in France in the end of the 90es. I doubt that it even reached the US at that time, much less Japan. Now, I remember how in one of these boards they discussed that the young man could be from France. The reasoning seemed odd to me (something about not flushing because of plumbing?? I noticed that while i think the perp did not flush out of spite, the Japanese on the boards provide a more practical explanation to his behaviors.) However, if, in fact, the young man was engaged in parkour and used this skill, in 2000, he probably could have come only from France.

SBM: As @Incoherent's video showed, you don't have to be into parkour or anything else to climb into the rear bathroom window -- the much more challenging entry point of the two. Didn't the man in the video just work for the TV channel? To me personally, it would be like assuming the killer was a F1 pilot if we find out he drove a car to the crime scene. Rei's balcony was the simpler of the two entry points and it explains the sequence of the murders perfectly. As for the killer being French, there is absolutely zero that points to France here. Zero. Unless you count the killer wearing Drakkar Noir as evidence of him being French.

Another person who could scale up the house easy would be a lineman of electric lines. They can climb up the balcony, and they are unnoticeable. Hence, I want to ask whether there is a line of lanterns behind the Miyazawas house, or something like it? This would serve as a good reason to even be behind their house that night.

I can't discount this with absolute certainty but the police say the killer is as young as 15.

One more consideration. If the blog about the killing was made by the perpetrator, he is thinking in Japanese categories. The thing is, most of the people I know would view year 2000 as the beginning of the next century and millennium. The young man says he wants to celebrate the new century, e.g., 2001. I am not sure if a person living on the base would think so. JMO.

世田谷一家殺人事件 黒ムツによる事件前と事件後の気になる書き込み | これ知っておけばOK!（簡単にすぐ分かる!）

blog.broadcreation.com

World: Which Is The True Third Millennium Year, 2000 Or 2001?

Which is the real millennium year, the outgoing 2000 or the incoming 2001? Despite the worldwide celebrations last January 1, the controversy over the beginning of the true Third Millennium is far from over. RFE/RL correspondent Eugen Tomiuc presents the arguments on both sides. Prague, 28...

www.rferl.org

The blog about the killings or the animal torture was NOT made by the killer. As I've said many times, this person was found by the Chief and 'eliminated' from the investigation. I don't have more details than that but it basically seems it was just some loser making stuff up online.

 

[FacelessPodcast]

I saw that in the video! I didn’t think it was so doable. It looks more difficult than the guy made it look in the video. The only thing is I do not see how he could have entered through the bathroom window and the crime have unfolded the way the crime scene indicates. Everyone would have heard him coming through that window, I think.

I also think the bathroom window is a red herring. Which explains the complete lack of fibres and prints.

 

[Incoherent]

SBM: As @Incoherent's video showed, you don't have to be into parkour or anything else to climb into the rear bathroom window -- the much more challenging entry point of the two. Didn't the man in the video just work for the TV channel? To me personally, it would be like assuming the killer was a F1 pilot if we find out he drove a car to the crime scene. Rei's balcony was the simpler of the two entry points and it explains the sequence of the murders perfectly. As for the killer being French, there is absolutely zero that points to France here. Zero. Unless you count the killer wearing Drakkar Noir as evidence of him being French.

I can't discount this with absolute certainty but the police say the killer is as young as 15.


The blog about the killings or the animal torture was NOT made by the killer. As I've said many times, this person was found by the Chief and 'eliminated' from the investigation. I don't have more details than that but it basically seems it was just some loser making stuff up online.

Some more thoughts.

Man I would’ve loved if those Kuromutsu posts were true. The Japanese used is so condescending and just mocks the Miyazawa family and what he did. But it makes sense it was some loser online posting on 2chan and finding humour in the whole thing. Back in the early 2000’s message boards were full of those jerks.

I’m finding it harder and harder to believe the killer could’ve entered via the bathroom window.
It would have been challenging, but not impossible, to enter that way. The re-creation by the 170cm actor shows that even he had to squeeze into that window it was so narrow.
(Side note: 27.5cm sneakers on a 170cm person looks ridiculous and borderline comical). And yet no fibres? I just can’t believe it. He had to cartwheel down onto the floor head first. There would have been something on that window.

I can totally believe the window was open though. It is typical to bathe at night in Japan and the Miyazawa bathroom was made of plastic which would need airing out after showering or bathing to prevent mold. Easiest way is to crack the window with the fly screen on. But that would also potentially mean the bathroom was wet if closer to the bathing time.

(Another side note: it is customary to share bath water in Japan with your family, as members use the separate shower hose to wash first and then relax in the water. The documents found in the tub full of water could have been water that was already there beforehand).

And onto the next point of the fly screen being pushed out. Those things are flimsy as hell. Rather than being pulled off to gain entry, I suspect the killer pushed it out when deciding his point of exit post murder and then decided against it. Hence zero fibres or blood around the window.

I am pretty convinced at this point that he entered via Rei’s balcony. Just WHY those balcony doors were open I don’t know, but like I previously showed in photos it would have definitely been used for laundry and the doors could have been left unlocked. Totally guilty of that myself too in my home here.

When it came to exiting he could’ve gone to the bathroom after dumping the documents in the tub, shoved the fly screen off, and then reconsidered after realising how tight the squeeze was.

So, how did he exit? Not the bathroom window, not the front door, so the balcony again? Easy enough to do, but wouldn’t he have left evidence? Was it ever checked properly?

 

[Dr. Snoop]

It was pretty unlikely to be a robbery for so many reasons: He didn’t just grab a kitchen knife from the home. He came to kill it would seem. He also left money behind.

The more I think about this, the more I'm inclined towards the theory that it might be both robbery and punishment in the perpetrator's disturbed mindset. It appears to be a form of punishment directed at the family's happiness and harmony—a stark contrast to the life the perpetrator didn't have.

It's not merely about taking lives; it extends to a deliberate disrespect for their home, evident in the unsettling chaos left behind—upturned belongings and a blatant disregard for order (toilet, bathroom). Even the act of consuming their ice cream carries a level of savageness, as some sources suggest it was done without a spoon, cups squashed into the mouth.

The perpetrator's actions seem senseless, yet they orchestrated a bizarre symphony of chaos. Strangely, amidst the disorder, the perpetrator left behind his neatly folded bloodied clothes, but did not leave the shoes. While it's possible that some of Mikkio's clothes were taken for an escape, I haven't found confirmation.

However, there's a clear financial motive in the act. Despite leaving some money behind, the perpetrator took a portion, which technically makes it a robbery, regardless of the oddities surrounding the crime scene. JMO.

 

[Dr. Snoop]

1) they also found very local, Miura beach sand, in his pockets, and local trees and bird droppings. If the sand will lead to him, this will be the greatest case, but so far, it is not a 100% proof to me.

In my view, this evidence is crucial because there are fish factories in the area, and it's a spot where fishing ships from places like China and the Philippines can dock. What caught my attention is how the sashimi knife was wrapped, a style often seen in Chinese and Filipino fish processing places. It goes without saying that such places often have numerous undocumented immigrants as part of their workforce.

Thinking about it logically, it seems the killer might not have bought the sashimi knife; they could have just taken it from a local factory. Just because the knife was sold doesn't mean the killer bought it. The same goes for his bag – it could have been taken too. Bags like his are commonly used by fish sellers or other vendors at markets. So, the idea that the bag and knife were possibly swiped adds another angle to the investigation.

Tuna Town: A Tour of Misaki Port on the Miura Peninsula

Misaki Port on the southwestern end of the Miura Peninsula in Kanagawa Prefecture has long prospered as a deep-sea fishing base. As one of 13 anchorages in Japan designated as a Class 3 fishing port, it harbors fishing vessels from around the country, many of which come to fish the rich coastal waters for tuna. The city of Miura where the port is located has a long association with the much coveted fish, earning it the nickname maguro no machi, or “tuna town.”
The port is easily reached by train from Tokyo and surrounding areas on the Keikyū Main and Kurihama lines.

 

[Dr. Snoop]

We know he took a certain amount but left a greater amount in the house. One of the many puzzles.

I couldn't find the specific amounts taken, aside from what was left behind. Could you please kindly provide details on how the exact amount taken was determined?

If he was economically deprived, how did he have a brand-new jacket, an expensive shirt, an expensive knife, French aftershave, and a full belly? Why he didn't take all the money and the valuables in the house?

What exactly was easy about the Miyazawa house for a robbery? Moreover, if it was a robbery, why did he enter at a time when the family were home? Why did he immediately murder a small, sleeping child? Why did he eat their ice cream and so on, so forth. Does the author know nothing about the case itself? Is he just riffing?

I share the scepticism around these questions. Admittedly, these few items do present a bit of a paradox when considering the notion of deprivation. Regarding the clothing, it's important to note that the brand doesn't necessarily indicate wealth, especially in the case of Uniqlo, which is not particularly expensive. Additionally, we can't ascertain who purchased the clothes; perhaps they were acquired by his siblings or obtained at a discounted rate, - just a possibility.

As for the unusual choice of perfume, one could argue that it was selected to combat the lingering smell of fish, especially if the killer worked in a fish processing environment (restaurants, fish market, factory, etc). This might align with the idea of preparing for a date, investing in a fragrance to leave a lasting impression. However, the possibility also exists that the perfume was stolen or a Christmas gift.

Speculating about these peculiar yet not entirely implausible items on the same person, it's worth considering that the killer, who demonstrated exceptional skill in wielding the knife during the murders, may have been accustomed to working with such blades. The logical connection between the sashimi knife and the sand from Tuna Town strengthens this hypothesis.

I'm less inclined to explore the direction of a California desert or military background. A young army recruit would likely lack the expertise displayed in handling knives, especially sashimi knives. Moreover, combat knives, preferred in military settings, differ significantly from fish knives, and the techniques required to handle them vary. If someone were planning a murder, it seems more plausible that they would choose a combat knife over a fish knife due to its sturdiness. JMO.

What exactly was easy about the Miyazawa house for a robbery?

The area appeared secluded, with houses that seemed affluent yet isolated. The entire neighbourhood exuded a sense of tranquillity, seemingly removed from the public eye. Adding to that, the bathroom window was conveniently situated on the opposite side, making it accessible for a nimble individual to climb up, remove the window frame and sneak in.

 

[Dr. Snoop]

Is a chef knife the best kitchen knife for a knife combat?

 

[Dr. Snoop]

I’m finding it harder and harder to believe the killer could’ve entered via the bathroom window.
It would have been challenging, but not impossible, to enter that way. The re-creation by the 170cm actor shows that even he had to squeeze into that window it was so narrow.
(Side note: 27.5cm sneakers on a 170cm person looks ridiculous and borderline comical). And yet no fibres? I just can’t believe it. He had to cartwheel down onto the floor head first. There would have been something on that window.

According to Average shoe size by height:


You are spot on. His feet indeed appear to be possibly a size larger than the average for his height. Although it's not much of a deviation. This could be attributed to his mixed ancestry or potentially a condition necessitating larger-sized shoes. Nevertheless, in my opinion, this wouldn't have hindered his ability to access the bathroom window. He had a jacket on made of polyester or nylon or something similar (water resistant fabric), and the police suspect he removed the screen frame for entry. I don't see significant obstacles for him to gain entry into the house. The window frame lacked any sharp irregularities that might have caught his clothing, as far as I can discern.

 

[Dr. Snoop]

I can't discount this with absolute certainty but the police say the killer is as young as 15.

My understanding of this estimate is that the police considered both his clothing style and his age, being less than 16, which could explain why he wasn't fingerprinted in South Korea, where he might have originated. Therefore, it's reasonable to suggest that he could be as young as 15. However, it's more likely that he was older and had been residing in Japan for some time. Considering the possibility of a developmental disorder, he might have been careless about avoiding detection, or perhaps he held a belief that the end of the world was imminent on the New Year.

Another theory could be that he was an illegal immigrant from China (many Europeans resided in Harbin and Shanghai both before and after the war, making mixed ancestry quite likely in those areas), working in Tuna Town. This could clarify why his fingerprints and DNA are unregistered. I would venture to propose that he desired to separate from his siblings, potentially live independently, and perhaps in another country, possibly his home country, necessitating funds for the journey back. It's conceivable that he fled on a Chinese boat.

I refrain from speculating whether he knew about the Miyazawa family selling their land and the possibility of having large amounts of cash in their house, or if he happened to be in the area before and knew about a few attractive houses in secluded locations that seemed suitable for a break-in. While I wish there was a way to seek assistance from the Chinese police, I have doubts about its feasibility in this case.