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The Gruesome Japanese Unsolved Mystery of the Setagaya Family Murder

In 2000, the Kamisoshigaya neighborhood of Setagaya, in the western suburbs of Tokyo, Japan, was a quiet residential area where nothing much ever really happened. Here there were few houses, with wide open spaces and plenty of quiet compared to the bustling, neon painted metropolis of Tokyo just a stone’s throw away. Here a humble office worker by the name of Mikio Miyazawa lived with his wife, Yasuko, and their two children, 8-year-old Niina and 6-year-old Rei. They lived in a modest house with few neighbors, one of them being Yasuko’s older sister, An, and her mother, with An’s husband away overseas. Indeed, most of the residents had moved out of the area, as Tokyo had been planning to incorporate it into the nearby Soshigaya Park, leaving only a few houses remaining. They lived a perfectly normal life, some might even say mundane, but dark clouds were looming for the Miyazawas, and they were about to become the center of one of the most mysterious and gruesome unsolved mysteries Japan has ever seen.

On December 31, 2000, Yasuko’s mother, Haruko, came by to visit after failing to reach the family over the phone, but no one seemed to be at home. After ringing the doorbell and shouting out to her daughter, she let herself in, thinking that they must have stepped out and would be back soon. She entered and was soon met by the horrific site of Mikio lying dead on the first floor, right next to the stairs. He was covered with blood and had evidently been stabbed numerous times. The panicked woman then went around shouting out to her daughter and grandchildren, only to find them dead as well, with Yasuko and Niina also both brutally stabbed, while Rei had been strangled to death. In a fit of horror and panic, Haruko contacted police and they arrived on the scene a short time later to find all manner of weird clues and piece together a sinister chain of events.

The Miyazawa house

A look at the house soon showed that whoever had done this had cut off the phone line and then likely entered through a bathroom window on the second floor, which the killer had accessed by climbing a tree outside at around 11:30 p.m. the previous evening, after which he had strangled the boy Rei in his bedroom as he slept and then gotten bolder with a sashimi knife to stab the others to death one by one. Yasuko and Niina thought to have been attacked as they slept as well, and considering many of their stab wounds were to the back and their bodies were found outside of the bedroom, it was thought that they had tried to escape and that the killer had chased them and continued to stab them as they tried to run away. Curiously, it seems as if the sashimi knife had broken during the attack, as there were fragments of it lodged in the bodies, and the killer had then switched to another knife from the family’s own kitchen. So far it seems like a pretty straightforward, albeit gory, home invasion and murder, but it would only get stranger from there.

After killing the family, it appears that the killer was in no hurry to leave. Indeed, police estimate that he spent several hours at the home, helping himself to some tea in the fridge and eating some ice cream, oddly by squeezing it out of the cups and biting it rather than using a spoon. He also spent some time rummaging through several drawers, the contents of which he dumped in a second-floor bathtub, and he took a number two in their toilet without flushing, also stuffing two handbags, Mikio’s wallet, and house keys into the toilet. It seems that the killer had incurred some injuries, as he had also used a first aid kit in the home and his blood would be found throughout the house, including on a bloodstained towel he left behind with his blood on it. The killer had also accessed the Internet on the family’s computer, where he had created a new folder and visited a theater’s website. The murderer had also apparently taken a nap on the sofa and then changed his clothes, leaving his old clothes behind neatly folded on the living room sofa, along with his jacket, shoes, a scarf, a hip bag, and the murder weapons beside them. All of the clothes were new and in pristine condition. After this, the killer had just disappeared into the night to vanish off the face of the earth without a trace.

An intense investigation was launched, which turned up further clues from the ample evidence left behind. An analysis of the killer’s blood showed that he was a man of mixed-race, with an East-Asian father and a mother of Southern European descent. However, a search of DNA databases showed no match. Likewise, the numerous fingerprints he had left behind turned up nothing either. This lack of any DNA or fingerprint information led police to believe that due to his mixed-race heritage, the perpetrator might not have been a Japanese citizen and so would not be in the system. The feces left behind in the toilet were also examined, finding the killer had eaten string beans and sesame seeds the previous day, but this was not of much help.

The various articles of clothing left behind, as well as the sashimi knife he had brought with him were tracked down to Kanagawa prefecture, and his clothes and belongings held other clues as well. It was found that the sweater was one of only 130 ever sold of that design, yet police could only track down 12 of the people who had purchased them, and in the pocket of the sweater were found traces of bird dropping, Japanese zelkova tree and willow leaves. The bloody shoes left behind allowed authorities to deduce that they were of a type, size, and brand only sold in South Korea, and more oddly, some trace amounts of sand found in the hip bag were scrutinized and found to have originated from the desert around Edwards Air Force Base, in California. What was going on here?

The investigation into the murders was by far the largest criminal investigation ever launched in Japan, involving tens of thousands of investigators over the years, massive resources, and cooperation with international law enforcement agencies. Yet, despite all of these clues, manpower, thousands of tips and leads, and an enormous reward offered for more information, no suspect has ever been found, and no one has any idea of who the perpetrator was or why he would target this unassuming family for such a violent and ghastly mass murder. At the time, such a brutal series of murders in this quiet area shocked the typically safe nation of Japan, and it completely dominated the news, creating a media frenzy and public fervor that would eventually change the law itself, causing the statute of limitations to be abolished for the crime of murder. To this day dozens of police detectives are still assigned to the case, and they are no closer to solving it now than they were back then.

The Miyazawa family

In the void of any real clues as to who committed these murders or why, speculation has run rampant. One idea was that this was a robbery that went south when the perpetrator was discovered by one of the family members. Yet, although the killer did steal the equivalent of around $1,500, he also left behind nearly $2,000 more. Why would he have done that if this was a robbery? Also, why would he have so gruesomely and savagely killed the whole family if this was just a robbery? The ferocity of the knife attacks has led some to think that this could have been some sort of grudge killing or targeted hit meant to make a statement, but Mikio was a quiet, unassuming office worker who had no known enemies and no known reason for someone to want to kill him and his entire family in such a wicked fashion. There was witness testimony that Mikio had recently been in a heated argument with a skateboarder at the nearby park, and indeed he often clashed with skaters there due to the noise they made. There was also some dirt from the killer’s clothes was tracked to this park, but this means little because the killer could have simply walked through the park on his way to the house, making it a dead end.

The case has remained nothing but dead ends. Although it is still pursued and still very much in the public consciousness in Japan, the case has never come even close to being solved. We still have no idea who killed this family or why. we don’t know why he stayed in the house for so long after the killings, or why he left behind so much evidence. His motives and methods are as alien to us now as they ever were. Who was this person and why did he kill these people? Where did he go and why can’t he be found? What is the meaning behind all of the strange clues left behind? The answers don’t seem likely to appear any time soon, and the eerie case remains one of the most insidious, mysterious, and well-known unsolved murder cases in Japanese history.