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Tuesday, October 27, 2015

The Setagaya Family Murders: the bizarre unsolved murder of a family of four

ᴄᴜʀʀᴇɴᴛ ʀᴇsᴇᴀʀᴄʜɪɴɢ: ɪᴛᴇᴍs ᴛʜᴀᴛ ᴀʀᴇ ᴄᴜʀʀᴇɴᴛʟʏ ʙᴇɪɴɢ ʀᴇsᴇᴀʀᴄʜᴇᴅ ᴍᴀʏ ʙᴇ ᴜᴘᴅᴀᴛᴇᴅ ᴘᴇʀɪᴏᴅɪᴄᴀʟʟʏ.

The Miyazawa Family

On December 30, 2000, the Miyazawa family went about their business as usual in the Setagaya district of Tokyo, oblivious to the fact that they were living out the last day of their lives.

Mikio Miyazawa, 44, worked for Interbrand, a London-based consulting firm. His wife, Yasuko, was a teacher, and they had two children: 8-year-old Niina and 6-year-old Rei.

The neighborhood they lived in was rather abandoned; there was an expansion of the skate park next door to them, and thus most of their neighbors had moved out. When the family moved there in 1990, the development held 200 families. Now, there were just four left: the Miyazawas, Yasuko's sister living next door, and two houses across the way.
The Miyazawas’ home was semi-detached. Though it was physically connected to Yasuko’s sister’s home, there was no way between the two houses from the inside.

The skate park had apparently been causing the Miyazawa family some grief, due to the noise. They planned to move in March 2001, so they only had a few months left in their home. A witness reported seeing Mikio arguing with skateboarder a few days before the crime. Another witness reported seeing the father arguing with the Bōsōzoku, a bike gang.
The evening of their last day alive, a witness saw the Miyazawas shopping at around 6pm at Seijogakuenmae Station, just under a mile from their home. A neighbor confirmed that at 6:30pm, their car was not in their driveway.
At 7pm that evening, Yasuko called her mother, who lived next door with her sister and her sister's husband. Niina had also visited her grandmother that evening, and had used her computer to watch a recorded TV program until 9:38pm.
At around 10:38-10:45, the family computer received an email that required a password to open. This is the latest time that we know the Miyazawas were alive.

Sightings before the crime

On December 25th, Yasuko had mentioned to her father-in-law that someone’s car was being repeatedly parked in front of their house.
On the 27th, a man described as in his forties was seen wandering around the house.
On the 29th, the day before the crime, a young man was seen near Seijogakuenmae Station wearing an outfit similar to the one found at the scene of the crime, along with a very small backpack. The eyewitness clearly remembered this because the man was underdressed for the weather, so she took note of it.
On the 30th, a man matching the description of the suspect was seen near Sengawa station, almost a mile from the Miyazawa home, stated to be between 35-40 years old. A man was also seen hurrying away on a path near the home at around 11:35pm – this is suspected to be the killer hurrying on his way to climb the fence (we’ll get to that in a bit).

The Layout of the Miyazawa Home

In 2013, investigators created a 3D-printed model of the Miyazawa’s home, a 1/28 scale replica. This is incredibly useful to understanding how the crime was played out. The locations of the victim’s bodies are labeled.

The home is portrayed exactly as investigators found it on December 31st. Note the open second-floor window. That is how our killer enters.

  The second floor of the Miyazawa home.  The killer entered through the bathroom in the rear.

A split view of part of the first and second floors.  The locations were the family's bodies were found are labeled.  The killer enters through the bathroom and turns right, first smothering the boy, 6-year-old Rei, in his sleep in the bunkbeds. Mikio had been working in the study on the first floor. Perhaps hearing a sound, he climbs the stairs, where he encounters the home invader. They fight, and the father’s body is found at the bottom of the stairwell.
See the two steps into the empty air above the first floor? Those lead up to the mezzanine. From the mezzanine floor, you can pull down a ladder that leads up to the third floor loft.

In this view of what is described as the “mezzanine floor,” we see the bodies of the mother and daughter where they were found at the foot of the ladder. That black line, as far as I can tell, lines up to the opening of the third floor, which we see here:

 Niina's blood was found on one of the futons, suggesting her and her mother hid upstairs from their attacker.

The Crime

How did our killer enter?  Take another look at the rear of the home:

The bathroom window was opened and the screen had fallen off inside. (I’m having a hard time determining if the screen had been removed or was actually cut. I’m leaning towards cut, since that seems to make more sense.) Footprints from the criminal were found below the window, as well as broken tree branches just below it. The killer apparently climbed the chain-link fence beneath the window and gained entry there, knocking off small tree branches in the process.
As I said before, the killer quietly made his way to the bedroom of the son, 6-year-old Rei, and strangled him in his sleep. Mikio, who had been in the study working on the first floor of the house, possibly heard a noise and made his way upstairs, where he encountered the invader.
The man had brought a sashimi knife with him, a knife with a long, thin blade. The killer and the father fought on the staircase, and the killer damaged his knife in the process. The father’s lifeless body was found lying at the bottom of the stairs to the second floor.
The killer then attacked the mother, Yasuko, and 8-year-old daugher, Niina, who were sleeping together in the third floor loft of the house. However, he couldn’t finish the job with his knife, and had to retreat to the kitchen on the second floor to grab another knife to finish them off - killing Yasuko with her own kitchen knife.
The family’s first aid kit was found open at the scene, with some of the daughter’s blood on the bandages. It appears that during the time the killer retreated to get a knife, Yasuko and Niina took the time to bandage their wounds and possibly hide somewhere. I haven't been able to find out where the first aid kit was kept or where in the house it was found. However, bandages were in the kitchen, with a bandage stuck to the fridge, and a bandage in the living room, as well. Yasuko and Niina may have raised the ladder to the loft in an attempt to hide from the killer, since Niina’s blood was also found on a futon upstairs. The phone lines were unplugged (though at what point this happened is unclear), so perhaps they were unable to call for help.
The killer returned with the knife from the kitchen and finished his gory task. The knifings of the female victims were much more intense than that of of his male victims, suggesting that he treats the victims differently based on sex. He would also continue to stab their bodies after they were dead.
Based on their stomach contents, the time of the family’s death was placed at 11:30pm.
During the attack, the murderer was injured at some point. His blood was found on bandages at the scene. There is also evidence that he used feminine hygiene products for this purpose as well. A perfect fingerprint of his was found on a towel (this might be a translation error, as I imagine it’s hard to leave a fingerprint on a towel; perhaps it was a paper towel?).

After the crime, he stayed in the house

After killing the family, the killer did not leave - he made himself at home. Perhaps after bandaging himself in the kitchen, he then opened the fridge and helped himself to its contents. Though there was some alcohol available (10 cans of beer), the killer didn’t take it - leading police to believe that he doesn’t drink. The killer ate some melon, drank barley tea, and ate some popsicles. He wandered around the home as he ate the popsicles, discarding two wrappers in the kitchen trash can, and winding up in Mikio’s study, where he discarded two other wrappers.
After going through some personal documents, the killer sat down in his victim’s chair and logged on the computer. (Can’t you picture him, idly sucking on a popsicle while tapping the keyboard with one hand, curiously poking around the computer, flipping through documents?)
Between midnight and 1am, the killer browsed the internet for 5min and 18 seconds. He visited the site of Shiki Theater Company and attempted to buy tickets to see a show. The Shiki Theater Company was an internet bookmark that had been saved by Mikio.
Then again, sometime in the morning, the killer used the computer for 4minutes and 16 seconds. He visited the webpage of the Mikio’s company and Yasuko’s school, then killed the power to the computer by pulling the power cord. The power cord was not found at the scene of the crime. The suspect’s fingerprints were not found on the keyboard, but they were found on the mouse.
Perhaps after attempting and failing to purchase theater tickets, the killer continuing strolling about the house, rummaging for information on his victims. In the living room, credit cards, bank books, driver’s licenses, and other personally identifying information were spread out as if the suspect had been sorting through them. In the second floor bathtub, more scattered papers were located, such as receipts, items from the mother’s school, towels, sanitary products used to stop bleeding, and other garbage were tossed. Perhaps now is when the killer used the toilet. He didn’t flush, and evidence of green beans and sesame seeds were found in his stool; apparently, a meal of sesame spinach, a cold dish the perpetrator consumed somewhere other than the Miyazawa’s home.
At some point, the killer took a nap on the couch in the living room.
It is possible that the killer left and returned to the scene of the crime. However, I don’t get the impression that this is seen as very likely. Not that the killer seems to mind risk, but that would be a serious indication of additional risk. No one is seen entering or leaving the home at this time, and there had been a few sightings of the killer before the attacks, as well as one potential sighting afterwards – keep in mind, the killer is injured. Given that there is evidence of the killer taking a nap on the couch, I think this is the explanation for the gap in his movements at the time. Of course, there is no way to know for sure.

What he left behind

Calm and not at all cautious through the entire affair, the killer left behind several personal belongings at the scene of the crime. It doesn’t seem the suspect was ever fearful of being caught or of leaving behind evidence, so it doesn’t seem like this would be an oversight. The suspect changed his clothes and left behind his outfight, neatly folded.

What he wore: Dress like a killer!

I want to list out the articles of clothing and brand names, but I’m having difficultly doing so. The brands are from a local skateboarding store, and the style is that skateboarder/surfer kind of look.
The suspect left behind:
  • sneakers, Slazenger brand, with Korean sizing (likely purchased in Korea)
  • a dark green hip bag – this is like a cooler version of a fanny pack, apparently (see picture above)
  • a black handkerchief
  • a hat
  • a scarf
  • a down jacket
  • black winter gloves
Police were also able to determine the cologne the suspect wore (a favorite brand of skateboarders).
Several of these items were available to be purchased in the Suginami ward by Ogikubo station, so police think the suspect shopped there. However, despite being able to locate specific stores where the killer shopped, they were no closer to revealing his identity.
Due to leaving behind his clothing, the police were able to determine that the killer is 5’7” with a waist size of 32.6in. He was probably in his twenties or thirties (in 2000), and obviously physically fit.

The Murder Weapon

The killer brought a sashimi knife with him. I believe the brand is Yanagiha Hawatari, and the store where this specific knife was purchased was located by police (it was in the shopping center at Ogikubo station). This was used to kill Mikio.

Genetic makeup of killer

The killer is mixed-race, with a mother of Southern European descent and a father who is either Korean or Chinese (probably more likely Korean).
Obviously, his fingerprints and DNA have been thoroughly searched and match nothing.

Trace Evidence

There was some strange and rather telling amounts of small trace evidence.
In the “hip bag” small traces of sand were found. Sand, of course, can be analyzed just like another else. This sand came from America. The southwest, actually; near Las Vegas, Nevada… specifically, sand from Edwards Air Force Base.
This is the most mind-blowing piece of evidence for me. Edwards Air Force Base?! Why?!
Sand was also found that was traced to a skate park in Japan. There are comments like “California is where skater culture began, so it’s clear this is a skater…” but what was he doing on an American Air Force base?!
The suspect seems to travel a lot… America, Korea, Japan… so maybe he is an Airman? I hate the thought of someone this crazy living in my country or serving in my military. However, I believe that you are fingerprinted when you joined the military, so I would expect that this avenue has been explored and is a dead end, as I don’t see any mention of the suspect being in the American Armed Forces.
Trace amounts of a “red flourescent agent” were also found on the suspect’s clothing. This apparently indicates that the suspect was involved in stage prop design, as that is where this particular chemical is used, and it was not something the family had or would have been around. Trace amounts were also found in the garage, however, there was no indication the suspect had ever been in the garage. This led investigators to believe that the suspect may have had contact with the family prior to the killing. It makes me wonder if there was cross contamination, however, this forensic examination was clearly top-notch, so I doubt contamination was the case.

Sighting After the Crime

On the 31st, six hours after the discovery of the crime and probably seven hours after the killer had fled the scene, a young man was treated for a knife wound at Tobunikko Station, around 75 miles to the north of the [family’s] house. The man was in his 30s and was wearing a black down jacket and jeans. The station staff treated him for the wound, which was deep enough to see the bone. The man did not give his name nor did he give a reason for his wound, and, incredible though it seems, he was simply treated and released.
Remember, at this time investigators thought the criminal had left the scene the night before, and it wasn’t until months later, when they had examined the forensic evidence on the computer, that they realized the suspect had stayed in the home. By this time it was ten months later and it was impossible to trace the suspect further.

Items Missing from the Home

This murder was not about money - many valuable items and cash were not taken from the home. The killer may have taken 150,000 yen ($1256 USD), but family members weren’t sure where the money was, and again, more cash than that was left in the home.
An old jacket was missing, and all of the family’s “Happy New Year” greeting cards were missing (I get the sense these are like Christmas cards to us Westerners).
The power cord to the computer is not mentioned here, but that was not found in the home, either.

Discovery of the Crime

At around 10pm, a witness strolling through the park heard an argument from the Miyazawa home. However, they didn’t hear anything being broken or any physical altercation. This makes police think the killer may have been on the scene earlier. I dislike this explanation because we still have that email being opened at 11:30pm, and I can’t imagine anyone would pause arguing with an intruder to open an email. I’m inclined to think the witness got the time wrong.
Around 11:30pm, the grandmother (Yasuko’s mother) next door heard a loud bang. Police reenacted the scene and found that this could have been either Mikio falling down the stairs or the attic ladder deploying. However, the sound wasn’t enough to make the family suspect anything and was not investigated further.
The following morning, Yasuko’s mother tried calling the family and found that she couldn’t get through (because the killer had cut the phone lines). Suspicious, she went next door and rang the doorbell. The front door was locked from the inside. (The police are not sure how the killer left, since there was no blood or fingerprints on the front door. I’m doubtful the killer left through the bathroom window, however; as we all know, absence of fingerprints doesn’t mean it wasn’t touched.)
The grandmother used her set of keys to open the door and discovered the crime scene.


There have been, essentially, no leads on who this person might be.
The suspect is mixed race, half Asian (probably Korean) and half white. He is young, in his 20s or 30s at the time of the crime, which would place him in his 30s or 40s now. He was into the skateboarding scene back then. He probably has issues with females. He doesn’t drink, or didn’t at the time of the crime.
Despite the overwhelming amount of forensic evidence found, the perpetrator of this deeply disturbing crime has never been found.



  1. The way that the murder stayed in the house for a period after the murders reminds me of the unsolved murders in Hinterkaifeck, Germany in 1922:


    1. When I posted this on Reddit I titled it "the Hinterkaifeck-esque murders" ;)

      Hinterkaifeck is such a popular mystery, but this is so much creepier because it's so recent, and there's so much evidence - yet it's still unsolved! He's out there somewhere!

  2. A lot of the items left behind could be stolen from somewhere and might not have originated with the killer. The perpetrator is, after all, a psychopath.

    One of the more interesting things about this case is Mr. Miyazawa himself. Did he speak English? He worked for an English brand, which potentially might indicate he spoke English. If the killer was of mixed ethnicity -- and not Japanese -- then it's very likely that he didn't speak Japanese (unless he was half Zainichi Korean). And the person whom Mr. Miyazawa had a dispute with in front of the skate park might not have spoken Japanese. I'm assuming that they likely argued in English. The American airman as a killer could be very possible. But a child or spouse of a diplomat is a much more likely possibility. Were any of the South Korean embassy staff married to a European of Southern European descent? I tried looking up the South Korean ambassador to Japan in 2000, but couldn't find anything. I'm sure someone out there has this information.

    Yokota airbase is about 45 minutes away by car. The various embassies are about 25 minutes away by car. While airmen and ambassadorial staff/families often live away from their jobs, they probably live somewhat near them.

  3. There were several witnesses who overheard Mr. Miyazawa arguing with a skateboarder, or hearing bits of an argument or loud voices that night. I haven't come across any mention of a foreign language being used, which leads me to believe that these arguments were in Japanese - and therefore, the perpetrator was fluent in Japanese.

    Given his activity on the computer and trying to purchase tickets from the theater website, I believe that the perpetrator must have been able to read Japanese, as he wouldn't have been capable of navigating the website otherwise. He also went through the Miyazawa's personally identifying information and left it strewn throughout the house, indicating that he was capable of reading Japanese and sorting out what was important and what isn't.

    I've had several people say they think the killer was leading a false trail, but I don't believe that personally, and I don't think police do, either. Though this case is strange, there are several telltale points that seem to indicate a younger, inexperienced, perhaps even first-time killer. There is a lack of sophistication on many points that wouldn't be there if this were a brilliant psychopath trying to lead us astray.

    I do like the theory that this was a servicemember's son. However, it doesn't seem like authorities are interested in that; I have to do more exploring, though.

    1. I just lost a 500 word post, thanks to an errant click. I'll try to rewrite it.

      It seems that the killer speaks Japanese and falls into the disorganized profile of a serial killer. A disorganized killer more than likely lives near the scene of the crime. They also have socialization issues which explains why they attacked the females with greater savagery than than males. The biggest clue IMO is the description of the possible perpetrator by hospital staff. Unfortunately, the details available are scant -- but there was no mention from the hospital staff that the killer betrayed an accent (you are likely correct). Therefore the murderer may have been raised and educated in Japan. The descriptions of the murderer do not suggest mixed heritage, so they most likely appear more East Asian than Southern European. Based on this information they are not likely to be an international university student (Komazawa University is the closest school with an international student presence), nor are they likely to be from a transient group passing through the country, such as an airman or diplomatic staff/family. Some possibilities include the son of a Zainichi Korean, an adopted child, or the son of a semi-permanent resident from Korea or the West. They would more than likely have a Korean last name, unless they adopted a Japanese last name. I think the focus of the investigation should emphasize the killer's ethnicity and proclivities (skateboarding) rather than some of the potentially false eye-witness description.

      While the theater website has an English language version, the plays themselves are only in Japanese -- so you are probably correct that the killer is a Japanese speaker. However, they were visiting the theater web site because it was bookmarked -- so they may have simply been testing out whether or not the credit card was any good. This might be a red herring.

      Another potential red herring is the sand from Nevada. Sand is frequently used to distress clothing. It's what causes scratches on your smartphone screen and it can be found in all manner of clothing and accessories. There are at least 64 different clothing manufacturers in Nevada, so I am skeptical that this leads directly to the killer.

      The skateboarding angle is one of the more interesting threads of discussion. To the East of Setagaya there's quite a few skateboarding parks. To the West, however, there are almost none (that I can see). I imagine that in 2000 there were even fewer skateboarding parks around. This may indicate where the killer hailed from.

      Thanks for the response, by the way. Really fascinating stuff.

  4. Terrible human tragedy. Reading through all the material and skipping ower the obvious disputes with skateboarders, bosozoku, I am intrigued by a few things.

    1. The Korea connection and comments elsewhere that this was related to Unification church.
    2. The compensation payoff from the government for moving for park expansion. Is it possible that someone negotiated a high pay off from the govt for him to move, and wanted their commission cut on this, or that the government wanted him out with having to pay him off. There could also be some yakuza link to this as they are often involved in land disputes. In either case, it looks to me like a hitman was used by whichever party decided to take him out.
    3. The timing of the incident right before the end of the tax year may be related to the payout issue.
    4. The entire family was targeted so that no future claims from heirs(such as kids or spouse) could be made.
    5. The fact that the killer stayed all night. I believe this is not his initial intent, but after cutting himself, he knew he needed medical help,called into whoever the boss was that hired him and was ordered to wait for the morning train rush hour to start to blend in with the crowds, and also to easily travel to a remote location for medical attention during daytime to again avoid arousing too much attention or suspicion.

  5. The fact that he was involved with the military, was of mixed-race, and was rather young leads me to believe this guy had connections with the higher up. He killed them and acted so nonchalantly because he was 100% positive that he would never be caught. It's so scary...