The Miyazawa Family Murder

On December the 31st, 2000, the bodies of Mikio Miyazawa (44), his wife Yasuko (41), and their two children Niina (8) and Rei (6), were discovered by Yasuko’s mother at their house in the Kamisoshigaya neighbourhood of Setagaya, in the western suburbs of Tokyo.

Mikio, Yasuko and Niina had all been stabbed to death, whereas Rei had been strangled. Police determined that the family was murdered at around 11:30pm the night before. After the murders, the killer stayed inside the house for several hours.

The Miyazawa family home. Credit: Wikipedia

It was discovered that the murderer had gained access to the house via a window in the second-floor bathroom, and had managed to reach the window by climbing a tree and removing the window screen.

After entering the house, the murderer entered Rei’s room, also located on the second floor, and strangled him using his bare hands. Upon hearing the disturbance in his son’s room, Mikio rushed up the stairs and began fighting with the attacker.

Mikio managed to injure the attacker but sadly died after being stabbed in the head with a sashimi knife. A report from the police claimed that part of the blade broke off inside Mikio’s head.

The attacker then started to attack Yasuko and Niina with the broken sashimi knife, before using a general kitchen knife from the house to kill them. They were stabbed mainly in the head and chest area, and their bodies were found crouching with their backs touching.

After committing the brutal murders, the attacker went into the kitchen and drank 4 bottles of barley tea, and 4 small ice cream cups from the freezer, which he consumed by squeezing the containers upwards and biting the ice cream. He also found a first aid kit in the kitchen, which opened to try to bandage his cut.

He also used the toilet and didn’t bother to flush.

Documents and personal belongings from Yasuko’s handbags, along with Mikio’s wallet, house keys and other random documents were thrown into the bathtub. A white towel smeared with the murderer’s blood and the empty ice cream cups were also thrown into the bathtub.

The Miyazawa Family. Credit:

At 1:18am, the attacker then logged on to the family computer. He made a new folder, and then visited a theatre website that was bookmarked by Mikio. After that, no one knows what the attacker was up to.

At 10am, the internet in the family home became connected again, and for years people believed that the perpetrator must have stayed at the house until that morning. However, in 2014, police said that they believe that it was not the perpetrator, but instead Yasuko’s mother dropped the mouse on accident when she discovered the bodies.

This means that the murderer left the house sometime between 1:30am and 10:00am.

The attacker left behind items of his own at the house, including a knife, muffler, hip bag, sweater, jacket, hat, gloves, shoes, and two handkerchiefs.

Police have been able to collect a lot of DNA and fingerprints from the murderer, but they have never been able to identify him.

Based on blood analysis, police discovered that the murderer has type A blood (which doesn’t match the Miyazawa family) and that the murderer is a male, and possibly mixed race. Maternal DNA indicates a mother of European descent, with paternal DNA showing a father of East Asian descent.

They also believe that the killer was between 15-35 years old at the time of the murders, and was physically slim and around 170 centimetres. They also believe he is right-handed.

The trace amount of sand found in the fanny pack left by the murderer was determined to come from California, America – specifically the Edwards Air Force Base.

The investigation into the Miyazawa family murders is still active and ongoing. In 2019, thirty-five officers were still reported to be working on the case.

The Miyazawa Family. Credit:


The Miyazawa Family, Setagaya, Tokoyo, 2000, the 2000s, Murders, Homicides, Unsolved Murders, Unsolved Homicides, True Crime, Real Crime, Unsolved True Crime, Unsolved Case, Unsolved Mystery, Strange Circumstances, Unidentified Killer, Japan

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