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

[MURDERER_SERVANT]

It is rather unusual for a perp to stay at the crime scene until morning and sneak out at broad daylight instead of night and he did not bother leaving his clothes and DNA behind , whick make me think he could be leaving the country that day and had no other place to go after the crime .
If I were LE , I would check the departing planes and passengers list of that day . JMO

 

[marco09]

I have a different theory.

I think that this was a totally random stranger, probably a vagrant/homeless/drifter and a bit unstable mentally, who committed an opportunistic crime given the remote location of the house. This is the reason he hasn't been found over the years (A bit similar to why the abductor of Madeline McCann wasn't found for more than 15 years was because everyone was looking for a ghost since he was already behind bars). Other reasons for my belief are:
- A hitman, contract killer or career thief wouldn't linger around the house after the murders that long but a homeless/drifting, unstable person would take the opportunity to take a nap, help himself to food and use the loo which is what he did. The act of not flushing the loo after use is something I would expect a homeless/drifter/vagrant to have done previously
- A person who would want to avoid being identified wouldn't leave his belongings behind. A vagrant person would not have any qualms about leaving his belonging and would take up new clothes. Use and discard. He would also not be so much interested in robbing the house and would take the minimum valuables he found.
- A vagrant would have amassed his clothes and belongings from here and there which is what led the investigators to all the wild goose chase: Korean sized shoes and sand from the US
- No one has reported him so far. If he was living with relatives who would have suspected him over the years, someone would have reported him
- DNA testing can reveal details from generations ago which may not be recent. Even if the DNA results was valid and he was of mixed race, it supports my idea of someone who became estranged from his family due to identity confusion/not fitting in either parents' culture. Biracial parents are also more likely to separate, at least for couples compromising of white females and Asian men
- Even though the US military is known to protect their own who have committed crimes, taking the lives of two young children is a very heinous act. Someone would have reported him
- Japanese Skaters and bosozokus are generally spoilt brats. I can see them throwing stones or vandalizing or even beating up the father but to take the lives of 2 young children is unimaginable. I used to ride motorbikes in Japan too so I know that its mostly the leather jackets and loud sounds that makes them look dangerous but they are mostly toothless tigers. Again, someone would have grown up, regretted what happened after 20 years and would have reported his suspicions if the culprit was one of them.
- Anyone who has lived in Japan for any appreciable length of time would know how closed minded many Japanese can be. They all think alike. No one dares to think different. I cannot see an investigator trying to go against the suspicion that it was a foreigner who did this.

 

[DSCrime]

Good luck @FacelessPodcast

I hope the podcast brings answers and some measure of justice for the Miyazawa family. First heard about this case on a Youtube video & never forgot it. It is haunting.

My thoughts after reading the entire thread:

The perpetrator is young. His behavior at the crime scene seems disorganized and impulsive. He left behind so much evidence, suggesting that he didn't have a high level of criminal sophistication.

Having said that, I think this perpetrator probably had some experience in robberies & burglaries. He may have committed other burglaries in the past, maybe with little to no violence. He may have broken into homes while people were out and robbed them. But he was likely never caught b/c his fingerprints/DNA weren't in the system.

The Miyazawa family murders may have been an escalation of his behavior. Breaking into a residence w/ people at home is audacious & risky. Doesn't seem like a first time offense, but a crime a perpetrator works up to. Could explain the mix of apparent preparation (brought a knife) and disorganization (left behind so much evidence.)

His motives were likely psychological, whatever they were. Too much violence to be just about robbing.

Also think that the clothing he left behind may have been stolen or bought with stolen money. He left the Miyazawa home with enough money to buy himself new stuff.

There's something about this guy's behavior that makes me think robbing others, taking from others satisfies him psychologically.


I would also like to know the answer to @dub 's questions below. Rei was killed differently from the rest of the family. He suffered less violence than they did. Why?

I would ask how they determined with such apparent certainty that Rei was the first to be killed.

Because aside from the absence of blood on him, every single thing I’ve read in this thread about the situation points to him being killed last.

Based on the information here (which is as far as my familiarity with the case goes) I feel like the killer either didn’t know that Rei existed, or if he did, he was unfamiliar with the layout of the house, and as a result didn’t know he was even there until well after the initial murders (say, an hour or so, after he had bandaged his hand and done other things around the house).

I think this is an especially important matter because at least to me, the circumstances around Rei’s murder have potentially massive implications toward determining both the killers primary target and how much advance familiarity he had with the family.

[/QUOTE]

 

[DSCrime]

One more thing.

It seems interesting to me that the grandmother wasn't a target. He focused on the Miyazawas, a home with 2 adults in their 40s, as opposed to next door with an elderly person. Who else was living next door?

 

[MURDERER_SERVANT]

Combining above posts ,the perp might be a vagrant or a homeless with those expensive clothes stolen by him . But taking into account his crime potential , it’s rather strange neither his fingerprints nor DNA mathched by then and until today. This strenthens my thoughts on his leaving Japan and never coming back JMO .

 

[FacelessPodcast]

I have a different theory.

Sorry it's taken me so long to reply -- I've been really busy working on the podcast / finishing a novel. Thanks for the post, Marco -- Your points in turn:

*It is, of course, possible that the killer was a vagrant. But I think the likelihood of this is practically zero for a few different reasons.

Firstly, the number of homeless people in Japan is under 4,000 according to official stats (though I imagine the true number is likely higher, it's not going to be anything close to the figures we have in somewhere like LA or San Francisco). Secondly, while it's possible he stole his clothes, the Uniqlo jacket he was wearing had only been in stores for a month. So, he would have had to have moved quickly to get that. He was also carrying a $50 knife. And wearing Drakkar Noir aftershave. And had a full stomach at the time of the murders. And no drugs or alcohol in his system. He also ignored the beer in the fridge. Does any of this conclusively tell us he was or wasn't homeless? No. I just disagree that any of it strongly suggests he's living on the streets.

On that note, how do we know a homeless person wouldn't flush the toilet? And if he was homeless, why would he take their belongings and defecate on them? Plus, I think the police would likely have commented on his clothes been worn or dirty if he'd been living on the streets. Or at least mentioned this possibility. The killer would have also had to stay out of trouble for the next 22 years and live completely off the grid without giving a fingerprint. Anywhere.

Also, if he were homeless, why would he only take *some* of the money? And leave behind a significant amount that was prominently kept in the house?

Your point about a relative reporting him -- why would you be so sure someone would give him up? What if his wife loved him or his parents? This could go either way.

As to the Japanese being closed-minded and all thinking alike. It's a country of 127 million people. Yes, in many respects social harmony is valued in a different way than it is in the US or the UK and speaking against what your boss says, for example, might not be as frequent as it would in the aforementioned places. But it's also frankly their biggest unsolved case. After 22 years, if someone had a new lead within the TMPD, I can't imagine they'd be still sitting on it for fear of making waves. But it's something of a moot point anyway as there is absolutely zero information on the TMPD website that suggests they're looking for a foreigner. Only that his shoes were likely made in Korea. Same goes for his DNA. I can't get into detail on this but I will say this: the Tokyo police don't say much on the matter -- especially not on their information appeal on their website which is live as of today. So, if the TMPD do hold a suspicion that a foreigner killed the Miyazawa family, it's not one that they're officially investigating.

And all that to one side, the killer being homeless doesn't explain why he would climb in through their 2nd floor window in the first place? Or murder an entire family. Much less stab Yasuko to the point of being facially unrecognisable / leave Niina without her two front teeth.

 

[FacelessPodcast]

Good luck @FacelessPodcast

I hope the podcast brings answers and some measure of justice for the Miyazawa family. First heard about this case on a Youtube video & never forgot it. It is haunting.

Thanks so much, DSCrime. Appreciate that -- here's hoping we can do a bit of good. As for your points -- interesting! My thoughts:

*Yes, on the night of the murders we know the killer is between 15-early 20s according to the TMPD. I've heard LE members and professors in the field seem to dislike the organised/disorganised binary but I totally agree that his actions are anything but clean and calm and collected in the house.

*As for experience in robberies, I spoke to someone who has decades of experience in this field and he disagreed based on a few things. Firstly, if you look at pictures of the way he opened drawers -- he did it in the wrong way -- from top to bottom meaning he would have to open then shut to go down to the next draw. (Instead of starting at the bottom and working up). Also, he brought a knife to the scene which is apparently uncommon. Plus, he entered the home at night at a time when it was basically obvious the house wouldn't be empty. And finally, his first action is to immediately murder a little boy. Plus, if he had committed previous robberies, even if he hadn't been caught, his prints would be on file and they would've matched the crimes at the very least.

*Totally agree the murders would have been part of a history of offending. It seems very unlikely he just went from nothing to mass murder over one night.

*Agree also that these murders were personal on some level for the killer. Whether he knew them personally or whether for what they represented.

*He left the house with some of their money but he also left behind a fair amount of money. It seems unlikely this was his main motive.

*I find your point about his satisfaction interesting-- it could well be that he gets off on eating their stuff, taking their objects, wearing their clothes. Not necessarily FOR those things but as part of a whole act.

*And as for the killer's discrepancy in the way he killed the family members, I would LOVE to know that too. Though I would also point out that the situation between Rei / Mikio / the females were all different. It's possible it was situational. He kills Rei quietly, then is as efficient as possible with Mikio as he's the main threat. Then, when he's removed, the killer is able to take his time with Yasuko and Niina. OR he simply hates women and that was his main motivation. In short, who knows. But I sure would love to.

 

[FacelessPodcast]

One more thing.

It seems interesting to me that the grandmother wasn't a target. He focused on the Miyazawas, a home with 2 adults in their 40s, as opposed to next door with an elderly person. Who else was living next door?

Such a good point. For various reasons, I can't really say too much more on this subject. But yes, 100% -- why this house but not the one next door. (The other one still standing across from the Miyazawa's house was totally empty). How does the killer know who's home? Why pick them? ...

 

[FacelessPodcast]

Combining above posts ,the perp might be a vagrant or a homeless with those expensive clothes stolen by him . But taking into account his crime potential , it’s rather strange neither his fingerprints nor DNA mathched by then and until today. This strenthens my thoughts on his leaving Japan and never coming back JMO .

Yeah, for sure I think if he's offended before, he's going to be on a list somewhere. Plus, I don't believe these mass murders were an isolated incident with nothing before or after them.

As for leaving the country, it's one of the big possibilities. The other is death. Or simply leaving in plain sight...

 

[Charlot123]

Thanks so much, DSCrime. Appreciate that -- here's hoping we can do a bit of good. As for your points -- interesting! My thoughts:

*Yes, on the night of the murders we know the killer is between 15-early 20s according to the TMPD. I've heard LE members and professors in the field seem to dislike the organised/disorganised binary but I totally agree that his actions are anything but clean and calm and collected in the house.

*As for experience in robberies, I spoke to someone who has decades of experience in this field and he disagreed based on a few things. Firstly, if you look at pictures of the way he opened drawers -- he did it in the wrong way -- from top to bottom meaning he would have to open then shut to go down to the next draw. (Instead of starting at the bottom and working up). Also, he brought a knife to the scene which is apparently uncommon. Plus, he entered the home at night at a time when it was basically obvious the house wouldn't be empty. And finally, his first action is to immediately murder a little boy. Plus, if he had committed previous robberies, even if he hadn't been caught, his prints would be on file and they would've matched the crimes at the very least.

*Totally agree the murders would have been part of a history of offending. It seems very unlikely he just went from nothing to mass murder over one night.

*Agree also that these murders were personal on some level for the killer. Whether he knew them personally or whether for what they represented.

*He left the house with some of their money but he also left behind a fair amount of money. It seems unlikely this was his main motive.

*I find your point about his satisfaction interesting-- it could well be that he gets off on eating their stuff, taking their objects, wearing their clothes. Not necessarily FOR those things but as part of a whole act.

*And as for the killer's discrepancy in the way he killed the family members, I would LOVE to know that too. Though I would also point out that the situation between Rei / Mikio / the females were all different. It's possible it was situational. He kills Rei quietly, then is as efficient as possible with Mikio as he's the main threat. Then, when he's removed, the killer is able to take his time with Yasuko and Niina. OR he simply hates women and that was his main motivation. In short, who knows. But I sure would love to.

Do you see some splitting between the way he treats the males and the females of the family? As if he associates, for lack of a better word, with these men, but women are nothing? It would be interesting to know if the same "association" is seen in the way he treated their things when he stayed in the house?
He is not related to them, this even oldest DNA tests could tell. But I wonder if in his delusional mind, he feels he somehow is?

 

[FacelessPodcast]

Do you see some splitting between the way he treats the males and the females of the family? As if he associates, for lack of a better word, with these men, but women are nothing? It would be interesting to know if the same "association" is seen in the way he treated their things when he stayed in the house?
He is not related to them, this even oldest DNA tests could tell. But I wonder if in his delusional mind, he feels he somehow is?

I have often wondered if there is an intentional difference between the ways in which he kills the males and the females. I have no certainty, either way. Part of me thinks that if there was a chance the killer could have subdued Mikio in the same way he did little Rei, he would've taken it. But then we know that Mikio was stabbed in the heart and ended up at the bottom of the stairs. That the killer didn't stab him beyond recognition the way he did with Yasuko... Maybe that was just situational? Many have assumed that the fact that the killer strangled Rei vs stabbing him like all the others suggests some kind of connection or even regret. But it also possible that he was just trying to keep things quiet and the killer had zero empathy for the boy, just as he did for anyone else. We also know that the killer was climbing over Mikio's body to look at a filing cabinet (and maybe even pulling out its drawers and leaving them on the body).

On the DNA front, I can't really get into too much more detail here but I can say that I've recently spoken to experts on this topic. Surely, the DNA left at the house would tell us whether or not a family member was involved, right? Well, from what I understand, given the latest tech, that would actually only apply to direct family - parents or siblings. Once you get into uncles / cousins / grandparents etc apparently it all gets a lot cloudier and difficult to determine hard and fast answers. Particularly if we're talking about the analysis from the early 2000s that the TMPD would have had access to.

As for the objects and household items, I've never heard of any kind of difference in the way the killer treats those belonging to the mother or Niina versus the males. If the TMPD have an inkling on that front, then no doubt that might have pointed them in the direction of a motive. And they certainly have never shared anything like that. The lack of apparent motive is what makes this case so strange. 22 years on, we've only got guesswork. And for every single guess I've heard (after 12 years following this case, I've heard a few!) there is always at least one fundamental flaw with the theory.

 

[FacelessPodcast]

Do you see some splitting between the way he treats the males and the females of the family? As if he associates, for lack of a better word, with these men, but women are nothing? It would be interesting to know if the same "association" is seen in the way he treated their things when he stayed in the house?
He is not related to them, this even oldest DNA tests could tell. But I wonder if in his delusional mind, he feels he somehow is?

But yes, Charlot, these are great questions because they get into the killer's head. And, given we have all the physical evidence in the world but zero in terms of his identity, I think his psychology, his inner needs, fears, hatred -- I think that's the way we can learn more about him.

 

[DSCrime]

Hi @FacelessPodcast thanks for all your replies. I really look forward to listening to the podcast when it comes out. Based on your posts here, I like the direction your research is going in.

Thank you for clarifying some points. The one below, about the crime scene suggesting the suspect didn't have much robbery experience was very interesting and changed my mind:

*As for experience in robberies, I spoke to someone who has decades of experience in this field and he disagreed based on a few things. Firstly, if you look at pictures of the way he opened drawers -- he did it in the wrong way -- from top to bottom meaning he would have to open then shut to go down to the next draw. (Instead of starting at the bottom and working up). Also, he brought a knife to the scene which is apparently uncommon. Plus, he entered the home at night at a time when it was basically obvious the house wouldn't be empty. And finally, his first action is to immediately murder a little boy. Plus, if he had committed previous robberies, even if he hadn't been caught, his prints would be on file and they would've matched the crimes at the very least.

This is such a good question @Charlot123

He is not related to them, this even oldest DNA tests could tell. But I wonder if in his delusional mind, he feels he somehow is?

I'm interested to learn more about Japanese law enforcement's DNA policies, both back then and now. Imagine that Japan has strong privacy laws as well.

Some countries like the U.K. collect DNA on arrest, regardless of future conviction. The U.S. uses familial DNA (searching for family connections of convicted felons to unidentified DNA in police databases) and also genetic genealogy. Different countries have different policies on youthful offenders... Would a youthful offender in Japan get their record completely expunged including DNA? Is that even a possibility?

Were there policy changes in Japan regarding youthful offenders in the last 20+ years?

 

[FacelessPodcast]

Hi @FacelessPodcast thanks for all your replies. I really look forward to listening to the podcast when it comes out. Based on your posts here, I like the direction your research is going in.

Thank you for clarifying some points. The one below, about the crime scene suggesting the suspect didn't have much robbery experience was very interesting and changed my mind:



This is such a good question @Charlot123



I'm interested to learn more about Japanese law enforcement's DNA policies, both back then and now. Imagine that Japan has strong privacy laws as well.

Some countries like the U.K. collect DNA on arrest, regardless of future conviction. The U.S. uses familial DNA (searching for family connections of convicted felons to unidentified DNA in police databases) and also genetic genealogy. Different countries have different policies on youthful offenders... Would a youthful offender in Japan get their record completely expunged including DNA? Is that even a possibility?

Were there policy changes in Japan regarding youthful offenders in the last 20+ years?

Thank you for your kind words, DS! I can't wait for the users here to listen. There have been one or two developments with the podcast so our launch date might be put back to the summer to see how things play out. I wish I could say more!

As for your points on Japanese LE policy on DNA, as I understand it, you're very much on the right lines. As you know, privacy laws in general are much stricter in Japan and DNA is no exception. For those that haven't read it, Richard Lloyd Parry's excellent book People Who Eat Darkness (on the Lucie Blackman case also in the year 2000) really shines a spotlight on the privacy matters there the hoops that LE have to pass through in order to get something as basic as the victim's own phone records.

So, essentially, if you're already on the offender database, then your DNA would pop at a crime scene. Or if you're apprehended for another crime. Short of that, my understanding is that DNA can't be used in the ways that it can in the UK or in the US. As for your question on youth offenders having their DNA taken, I'm afraid I have no idea but that would definitely be a question I'd love to know the answer to...

 

[vls12345]

@FacelessPodcast , just wanted to check in and see how your podcast is going.

Any new information you've found? Is your podcast still on track for release later this year?

 

[FacelessPodcast]

@FacelessPodcast , just wanted to check in and see how your podcast is going.

Any new information you've found? Is your podcast still on track for release later this year?

It's coming along well -- thank you, vls! Given we've had Covid-travel bans and reluctance to talk about the case, we've actually managed to find out quite a lot.

Originally, we were coming out in the summer but it's been put back to early October. I will, of course, update when I have more.

 

[vls12345]

It's coming along well -- thank you, vls! Given we've had Covid-travel bans and reluctance to talk about the case, we've actually managed to find out quite a lot.

Originally, we were coming out in the summer but it's been put back to early October. I will, of course, update when I have more.

Glad it's going well & that you've managed to find out some info. Looking forward to your podcast!

 

[ck932]

It is impossible for one person to have killed the whole family. The lady and the daughter could have locked themselves up in their room while the killer was strangling their son or fighting the man at the stairs. It is unlikely this was carried out by one single person. The fact the killer stayed in the house for a few hours proves he had company. If robbery was the motive, they could have done the same thing to the house next door where only an old lady lived. Mikko had argued with a group of motorcycle gang few days before the murder. It is possible a few of the biker guys were so angered that they decided to teach him a lesson.

 

[FacelessPodcast]

It is impossible for one person to have killed the whole family. The lady and the daughter could have locked themselves up in their room while the killer was strangling their son or fighting the man at the stairs. It is unlikely this was carried out by one single person. The fact the killer stayed in the house for a few hours proves he had company. If robbery was the motive, they could have done the same thing to the house next door where only an old lady lived. Mikko had argued with a group of motorcycle gang few days before the murder. It is possible a few of the biker guys were so angered that they decided to teach him a lesson.

Thanks for the post, ck932! However, very respectfully I would disagree with your point that it's impossible for one person to kill the whole family -- and for a few reasons:

1) Firstly, the sheer amount of evidence. There was blood, hair, fingerprints, excrement, saliva, and clothes left behind from one man -- the killer. After 22 years, it's hard to believe that the Tokyo MPD would hide the existence of other assailants in the house. And if they're not hiding that, then how is it possible for the killer to leave behind so much evidence, while at the same time his co-conspirators leave behind nothing?

2) Yasuko and Niina were upstairs in the attic at the time of the attack. This was accessed by a folding ladder. We don't know if this was lockable or if there was any way to prevent someone downstairs pulling it down, even if they had tried to pull it up. That's making the assumption that they had any idea what was happening downstairs. Likely that they heard noises. But did they have any conception of what was happening? I think if you factor in the sheer human shock of seeing a masked man with a knife in your house in the middle of the night, coming out of your kid's bedroom -- it's entirely conceivable that a normal salaryman would be overwhelmed by that, even if they fought (like it seems Mikio did). The same goes for Yasuko. Why would she assume this stranger is here to murder them? Why wouldn't she assume it's a robbery?

3) Why does the fact the killer stayed in the house prove he had company?

4) I can't get into too much detail here but it's not correct that an old lady lived next door alone. There was actually another family directly next door. Including Yasuko's sister and mother (the old lady).

5) I've read the theory that Mikio may have had some kind of disagreement with a Bōsōzoku gang. To my knowledge, it's never been proven or established that this ever actually happened. Unless you have a source for it that I haven't seen?

6) Finally, we simply don't know the motive. As you say, if it WAS robbery, then the killer did several things that make zero sense from start to finish. Then again, it's also a fact that he did steal money from the Miyazawa family and that he did go through their belongings.

The problem with this case, and part of the reason I've been so taken with it for so many years, is that when you hold any single piece of it up to the light to make sense of it, you immediately find contradictions. It's an enigma. That's part of the reason why I had to make a podcast about the case (which will be out in a few weeks!)

 

[ck932]

Thanks for the post, ck932! However, very respectfully I would disagree with your point that it's impossible for one person to kill the whole family -- and for a few reasons:

1) Firstly, the sheer amount of evidence. There was blood, hair, fingerprints, excrement, saliva, and clothes left behind from one man -- the killer. After 22 years, it's hard to believe that the Tokyo MPD would hide the existence of other assailants in the house. And if they're not hiding that, then how is it possible for the killer to leave behind so much evidence, while at the same time his co-conspirators leave behind nothing?

2) Yasuko and Niina were upstairs in the attic at the time of the attack. This was accessed by a folding ladder. We don't know if this was lockable or if there was any way to prevent someone downstairs pulling it down, even if they had tried to pull it up. That's making the assumption that they had any idea what was happening downstairs. Likely that they heard noises. But did they have any conception of what was happening? I think if you factor in the sheer human shock of seeing a masked man with a knife in your house in the middle of the night, coming out of your kid's bedroom -- it's entirely conceivable that a normal salaryman would be overwhelmed by that, even if they fought (like it seems Mikio did). The same goes for Yasuko. Why would she assume this stranger is here to murder them? Why wouldn't she assume it's a robbery?

3) Why does the fact the killer stayed in the house prove he had company?

4) I can't get into too much detail here but it's not correct that an old lady lived next door alone. There was actually another family directly next door. Including Yasuko's sister and mother (the old lady).

5) I've read the theory that Mikio may have had some kind of disagreement with a Bōsōzoku gang. To my knowledge, it's never been proven or established that this ever actually happened. Unless you have a source for it that I haven't seen?

6) Finally, we simply don't know the motive. As you say, if it WAS robbery, then the killer did several things that make zero sense from start to finish. Then again, it's also a fact that he did steal money from the Miyazawa family and that he did go through their belongings.

The problem with this case, and part of the reason I've been so taken with it for so many years, is that when you hold any single piece of it up to the light to make sense of it, you immediately find contradictions. It's an enigma. That's part of the reason why I had to make a podcast about the case (which will be out in a few weeks!)

The available fingerprints and DNA were from only one person? Maybe, if that is what they found. But remember the killer brought gloves. Didn't use them. What if the other killers had their gloves on and they never had any injuries. The reasoning for my theory stems from the fact. The killer spent considerable amount of time in the young boy's room. There were too many footprints left by the killer in the young boy's room. He lurked around before wreaking havoc. Also, there was a tip from cabbie that he picked up 3 passengers well past the midnight on the day of the murders. The cabbie recalled seeing one of the passengers had bandages on his hand. The Japan police did not take this account seriously.
You can read about it here . The Setagaya Murders — Unresolved

It is nearly impossible for a killer who was mere 5'6-5'7 , slim build , carrying only a knife, which is not well suited to kill humans massacring a family of 4 in 10 minutes. The house does not look easier to navigate. Were the lights turned off where the woman and the girl were sleeping in the second floor? The killer turned on the lights? There are too many difficulties the a single killer has to overcome. There are reports that the lady in the house used the first aid kit during the attacks. Why didn't she simply lock the door in the room? There is no way the killer could have gotten into the room. The theory of more than killer seems more plausible. One of the killers is in the boy's room while another one goes after Mikio and the other goes after the woman and the girl. The small window in bathroom looks like a big window for even a middle aged person to break in. The killers must have cased the house beforehand during daytime before making the move. They knew they had to break in later in the night. They were aware of the neighborhood. Lurking in the house alone after the massacre is not something anyone would want to do unless the killer had company. Killers usually flee the scene of the crime immediately out of fear they might get caught. A gang of killers would always feel emboldened to stick around because they look after each other. I read a report that killer even slept on the couch. Again, there are lot of speculations. Nobody knows what really took place after the murders.
The police are not sure if there was only one killer.

The killer(s) took some money for expenses and did not bother to take more. This looks like more of crime of passion not robbery.

This one case is very disturbing to say the least. A family of 4 including 2 kids were slaughtered and their property was desecrated and their hard earned money stolen. The perpetrator(s) have/has walked away scot-free. It is astounding to imagine that with enough fingerprints , DNA and material evidence they could not find a single suspect. Why don't they get the best detectives in the world to investigate? Scotland Yard, CIA? They have to run fingerprints search in global database to find a match. It is depressing that the Japanese police have not been competent enough. Justice has to be delivered before the killer(s) dies/die. Hoping there would be a breakthrough with the advancement in science and technology through the years. 22 years is way too long.